Protection, Control and Monitoring Equipment Design for Power Systems
Emdescol is a design house with more than 20 years of experience. We design and develop numerical relays, fault locators, SCADA, battery chargers and recorders for railway traction and for power utilities. Our customers manufacture and sell them.
Disturbance record. Line fault cleared by zone 1 distance protection. Illustrative.
Two Domains, One Discipline
The physics of a fault is the same everywhere. The networks, the specifications and the operating practice are not, so we treat each domain as its own specialism.
Railway Traction
Single-phase 25 kV and 2 x 25 kV autotransformer systems, where moving train loads look like faults, harmonics are heavy and every post is unattended. Equipment is designed to RDSO specifications.
- Feeder, transformer, Delta-I and panto flash-over relays
- Automatic fault locator for AT-fed sections
- Traction SCADA: RCC and RTUs at TSS, SSP, SP and ATP
Power Utilities
Three-phase generation, transmission and distribution networks run by state electricity boards and their generation, transmission and distribution companies, each with its own protection problem.
- Generator, line, transformer, bus bar and feeder protection
- Disturbance recorders and phasor measurement
- Substation automation, RTUs and control centre software
We Design. Our Customers Manufacture.
We do not manufacture or sell equipment. You bring a concept or a specification, and we hand back a complete, tested design that is ready for your production line. The only things we sell under our own name are our software tools and protocol libraries.
A relay is an analog front end, a sampling system, a set of algorithms and a trip circuit that must agree with each other inside a few milliseconds. We keep the hardware, PCB, firmware, algorithm and protocol work in one team, so nothing is lost between a board designer, a firmware vendor and a test house.
Concept
Design conceptualization and specification.
Hardware
CT and PT inputs, sampling, binary I/O, PCB design.
Firmware and algorithms
Phasor estimation, protection elements, protocols.
Compliance
Support through type testing and acceptance.
What We Design
Protection relays
Numerical relays for feeders, lines, transformers, generators, capacitor banks and supplies, for traction and utility networks.
Fault locators
Distance to fault in kilometres, for traction sections and for transmission lines.
SCADA
Redundant control centre software in secured network zones, and the remote terminal units in the field.
Advanced battery chargers
Float-cum-boost chargers for the station battery that every relay and trip coil depends on.
Disturbance recorders
Triggered capture of analog and digital channels, with pre-fault and post-fault windows.
Phasor equipment
Time-synchronized measurement of magnitude, phase angle and frequency.
Communication protocols
IEC 60870-5-101, 103 and 104, IEC 61850 and MODBUS, on every link from relay to control centre.
Custom devices
Specialized equipment designed to your specification when no standard product does the job.
Our Own Software Products
Alongside design work, we license the tools and protocol code we built for ourselves.
EMDESWAVE
COMTRADE file viewer with cursors, phasors, harmonics and impedance locus, for analysing fault records.
EMDESCOM
Multi communication logger that records and decodes COM, UDP and TCP/IP traffic on one time axis.
Protocol libraries
Portable C libraries for IEC 60870-5-101, 103 and 104, IEC 61850, MODBUS, DNP3 and IEEE C37.118.
Latest From Emdescol
Planning a New Relay, Recorder or Controller?
Send us the concept or the specification. We will tell you how we would take it to a design ready for your production.
Railway Traction
Protection, fault location and remote control for 25 kV and 2 x 25 kV AC traction power supply.
Two feeding systems, and we work on both
Most electrified routes use the conventional 25 kV system. High-density and heavy-haul routes are moving to the 2 x 25 kV autotransformer (AT) system, which carries power at 50 kV and delivers it to the train at 25 kV. The newer system changes the transformer, the conductors, the fault types and the way a fault is located, so its protection is a specialism of its own.
| 25 kV system | 2 x 25 kV AT system | |
|---|---|---|
| Traction transformer | Single-phase, across two grid phases | Scott-connected or V-connected, giving two single-phase outputs |
| Conductors | Catenary, with return through the rail | Catenary at +25 kV and a feeder wire at -25 kV, with the rail between them |
| Voltage sent out | 25 kV to rail | 50 kV between catenary and feeder, 25 kV to rail at the train |
| Posts along the route | TSS, SSP, SP | TSS, SSP, SP and autotransformer posts (ATP), with an autotransformer every 13 to 17 km |
| Fault types | Catenary to earth | Catenary to earth, feeder to earth, catenary to feeder |
| Impedance seen by the relay | Rises in proportion to distance | Not proportional to distance, because each autotransformer changes the current path |
| Fault location | From measured loop reactance | From the ratio of autotransformer neutral currents on either side of the fault |
| Switching | Single-pole breakers and interrupters | Double-pole breakers and interrupters, switching catenary and feeder together |
| Added protection | Autotransformer differential, and protection at SSP, SP and ATP |
Why feeder protection is difficult
The load on a traction feeder is large, inductive and moves along the line. Several trains bunched on one sector, or a heavy freight train starting on a gradient, can present an impedance close to that of a fault at the far end.
- Fault and load are separated by impedance angle. The distance element uses a parallelogram or polygonal characteristic with a narrow resistive reach, so load impedance stays outside it.
- High-resistance faults, such as a fallen branch or an arcing contact, fall outside every distance zone. A Delta-I element catches them from the sudden vector change in current.
- Locomotive converters and transformer inrush both distort the current. Second and third harmonic restraint stops the Delta-I element from mistaking them for a fault.
- If two supply phases are bridged across a neutral section, the relay sees current lagging its voltage by well over 90 degrees. The wrong phase coupling element is set on that angle.
- A pantograph crossing an insulated overlap from a live section to a dead one draws an arc that can burn the contact wire. Panto flashover protection trips the live side before the arc is established.
What the 2 x 25 kV system adds
We have specialized in the newer AT-fed system as well as the conventional one. The differences below are the ones that decide the relay and fault locator design.
- Scott-connected transformer differential protection, where the two secondary outputs are 90 degrees apart and the current balance is not a simple ratio
- Distance protection measuring on both catenary and feeder, with directional zones and a polygonal characteristic
- Recognition of all three fault types: catenary to earth, feeder to earth and catenary to feeder
- Differential protection for each 55 kV autotransformer
- Under-voltage supervision used against wrong phase coupling
- Two-shot auto-reclose
- High-impedance bus bar differential protection
- Protection relays at SSP, SP and ATP where those posts have circuit breakers
- Fault location by the AT neutral current ratio method, with measurements from several posts
From trip to restoration
The relay, the fault locator and the SCADA system work as one chain. This is the sequence after a fault on the OHE.
- The feeder relay trips the feeder circuit breaker and stores the fault record.
- Auto-reclose tries the feeder again. A transient fault clears and traffic continues.
- If the breaker trips again, auto-reclose locks out and the RTU reports it to the RCC.
- The fault locator reports the distance to the fault.
- The SCADA fault localization sequence opens interrupters to isolate the faulty sub-sector with the fewest switching operations.
- Supply is restored to the healthy sub-sectors, and the maintenance crew is sent to the reported kilometre.
Power Utilities
Protection, recording and control for generation, transmission and distribution.
Three networks, three protection problems
The state electricity boards, and the generation, transmission and distribution companies formed from them, run networks that behave very differently. A generator must be protected from its own abnormal operation. A transmission line must be cleared in a few cycles to keep the grid stable. A distribution feeder must be protected economically, thousands of times over. We design equipment for the manufacturers who supply all three.
Generation
Most generator protection is not about short circuits. It guards against conditions that are not faults at all but will damage the machine if they continue: motoring, unbalanced load, over-fluxing, abnormal voltage and frequency.
A generator relay therefore carries many elements, each watching a different quantity, and the design problem is measuring all of them accurately while frequency moves during start-up and shutdown.
- Multifunction generator protection in one relay
- Generator differential (87G)
- Reverse power (32), against motoring on loss of prime mover
- Negative phase sequence (46), with a thermal model of rotor heating
- Over-fluxing (24), from the ratio of voltage to frequency
- Voltage-restrained overcurrent (51V) as system backup
- Under and over frequency (81) and under and over voltage (27, 59)
- Generator transformer differential (87T) with inrush restraint
- Frequency tracking, so that measurement stays accurate off nominal frequency
Transmission
At 132 kV and above, a fault that stays on the system for too long threatens the stability of the whole grid. Protection is judged on operating time in milliseconds and on never tripping for a fault outside its zone.
That calls for distance and differential protection working with communication channels between line ends, and for recorders that show afterwards exactly what each relay did.
- Distance protection (21) with quadrilateral and mho characteristics, in several zones
- Teleprotection schemes over power line carrier or optical fibre: permissive and blocking
- Line differential protection (87L) over a fibre channel
- Power swing blocking and out-of-step detection
- Directional earth fault (67N) for high-resistance faults that distance elements miss
- Single-pole and three-pole auto-reclose (79) with synchronism check
- Bus bar differential (87B)
- Transformer differential (87T), restricted earth fault (64R) and over-fluxing (24)
- Automatic voltage regulation of transformer tap changers
- Fault location on the line, in kilometres from the substation
- Disturbance recorders and event loggers at each substation
- Phasor measurement units for wide-area monitoring of the grid
Distribution
A distribution company has thousands of 33 kV and 11 kV feeders. The relay on each one has to be simple, low in cost and reliable for years without attention.
The network is also changing. Rooftop solar and other embedded generation mean power can flow back up a feeder, and utilities now want every feeder monitored and switched remotely.
- Overcurrent and earth fault relays (50, 51, 50N, 51N) with IDMT curves
- Directional overcurrent (67) for parallel and ring feeders
- Sensitive earth fault for high-resistance faults on overhead lines
- Auto-reclose for transient faults on overhead feeders
- Under-frequency and rate-of-change-of-frequency load shedding
- Under and over voltage, phase failure and phase unbalance relays
- Reverse power protection for feeders with embedded generation
- Motor protection for industrial and auxiliary drives
- Capacitor bank protection and automatic switching
- Differential and overcurrent protection for 33/11 kV transformers
- Feeder RTUs for remote monitoring and switching
Recording and phasor measurement
After a grid disturbance, the utility and the load despatch centre need a common, time-aligned account of what happened across many substations.
- Disturbance recorders with pre-fault and post-fault capture on all analog and digital channels
- Sequence-of-events recording with millisecond time stamps
- GPS or PTP time synchronization, so records from different stations line up
- Records in COMTRADE format
- Synchrophasors, frequency and rate of change of frequency to IEEE C37.118
Substation automation and SCADA
The same two halves as in traction, with different names: a control centre where operators see and switch the network, and RTUs or a substation automation system in the field.
- RTUs for generating stations, grid substations and distribution substations
- Substation automation on IEC 61850, with relays reporting over the station bus
- Gateway to the load despatch or control centre on IEC 60870-5-101 and 104
- Control centre software: single-line displays, alarms, events, trends and history
- Interface to legacy relays on IEC 60870-5-103 and MODBUS
- Redundant servers and secured network zones at the control centre.
Substation DC supply
Protection, breaker tripping and communication all run from the station batteries. A substation that loses its DC supply has no protection.
- Float-cum-boost chargers for 110 V and 220 V protection batteries
- Chargers for 48 V communication batteries
- DC earth fault and battery monitoring relays
- Trip circuit supervision and PT fuse failure relays
- Charger and battery status reported to the RTU
SCADA
Control centre software and remote terminal units, designed for railway traction and adaptable to power utilities.
A control centre built in zones
A SCADA system switches live high-voltage equipment, so it must keep running through any single failure and must not be reachable from an office network. We design it as layered zones: the control network in the militarized zone, a de-militarized zone that is the only path to the outside, and firewalls between each layer.
Redundancy
No single failure of a server, a network switch, a communication channel or a power supply should stop the operator from seeing and switching the network.
- Dual redundant SCADA servers in hot standby, with the standby holding the same real-time database as the main
- Automatic failover without loss of data or of the operator's session, and manual changeover for maintenance
- Dual redundant front-end processors for RTU communication
- Dual redundant LAN, with every server and workstation connected to both
- Main and standby communication channels to each RTU, with automatic changeover on channel failure
- Redundant historian storage, so no events are lost during a changeover
- Backup control centre at a second location, kept synchronized for disaster recovery
- Uninterruptible power supply with battery backup for the whole control room
- Health monitoring of every server, link and RTU, shown on a system status display
Security zones
The militarized zone holds everything that can operate a breaker. Nothing outside it can open a connection into it. Data needed elsewhere is pushed out to the de-militarized zone, and outside users reach only that copy.
- Militarized zone (MZ): SCADA servers, front-end processors, historian and operator workstations on an isolated control network
- De-militarized zone (DMZ): web server, replica historian, patch and antivirus server, and remote access gateway
- Firewalls between the external network, the DMZ and the MZ, with only named services allowed through
- Data flows outward from the MZ to the DMZ replica; no control command is accepted from the DMZ
- Read-only web displays for management and maintenance staff, served from the DMZ
- Remote maintenance only through the DMZ gateway, over an encrypted and authenticated session
- Role-based access with individual logins, and an area of responsibility for each operator
- Audit trail of every login, command, setting change and acknowledgement
- Hardened servers and workstations: unused ports and services disabled, removable media controlled
- Patches and antivirus updates staged in the DMZ before they reach the control network
- Secure communication and device security in line with IEC 62351 and IEC 62443
Operator functions
The functions every control centre needs, whether the network is a railway division or a utility's substations.
- Single-line and mimic displays with live status, and colouring of live, dead and earthed sections
- Supervisory control with select-before-operate, check-back and command timeout
- Software interlocks that block an unsafe switching operation before the command is sent
- Tagging of equipment under maintenance, so that it cannot be operated remotely
- Alarm management: priorities, grouping, filtering, acknowledgement and audible annunciation
- Sequence-of-events list with time stamps from the RTU, to one millisecond
- Limit checking on analog values, with warning and alarm thresholds
- Real-time and historical trends, and replay of a past period
- Calculated points and totals derived from measured values
- Daily, shift and monthly reports: energy, maximum demand, trippings and equipment operations
- Multi-monitor workstations and a mimic or video wall for the whole network
- GPS-synchronized time across servers, workstations and RTUs
- Database and display editors, so the customer can add a post or a feeder without new software
- Operator training mode on a simulated network
Traction functions
The traction power controller (TPC) at the RCC runs the power supply of a whole division. These functions are specific to 25 kV and 2 x 25 kV traction and are where most of our SCADA work lies.
- Control of every TSS, SSP, SP and ATP on the division from one RCC
- Telecommands to grid-side and 25 kV circuit breakers, interrupters and transformer tap changers
- Automatic fault localization: after an auto-reclose lockout, the software finds and isolates the faulty sub-sector by opening the minimum number of interrupters
- Display of the fault distance from the automatic fault locator alongside the trip event
- Auto-reclose release and lockout indication for each feeder breaker
- Feed extension across a neutral section through the bridging interrupter, interlocked against wrong phase coupling
- Catenary voltage on both sides of the neutral section at each SP
- Interlock release requests at boundary posts between adjacent RCCs
- Power block management: sub-sectors under a power block are tagged and locked against re-energization
- Maximum demand monitoring at each TSS, with warning before the contract demand is exceeded
- Low OHE voltage and power factor monitoring, and capacitor bank switching
- Up line and down line, and catenary and feeder on AT sections, shown separately
- Retrieval of events and fault records from the numerical relays through the RTU
- Outage and tripping statistics for each feeder and sub-sector
Utility functions
The same platform serves a utility's transmission or distribution control centre, with these additions.
- Integration with IEC 61850 substation automation systems through a gateway
- Data exchange with the load despatch centre on IEC 60870-5-101 and 104
- Feeder-wise load, energy and outage records for 33 kV and 11 kV networks
- Under-frequency and scheduled load shedding by feeder group
- Transformer tap position and voltage control, and capacitor bank switching
- Feeder RTUs for remote switching of distribution feeders and ring main units
- Reliability reports on interruptions and their duration
Remote terminal units
The RTU is the control centre's hands and eyes at an unattended post. It has to keep working on the station battery, through electrical noise, with no one on site to restart it.
- Modular digital input, command output and analog input cards, sized to the post
- Telesignal inputs for breaker, interrupter, isolator and alarm status, with double-point indication
- Telecommand outputs with select-before-operate and check-back before execution
- Telemetry of voltage, current and other values, through transducers or direct CT and PT inputs
- Sequence-of-events time stamping to one millisecond
- Events buffered during a communication failure and sent when the link returns
- Dual communication ports for main and standby channels, and reporting to more than one master
- Optional redundant processor and power supply modules
- Gateway to numerical relays, fault locators, meters and battery chargers on IEC 60870-5-103, IEC 61850 and MODBUS
- Programmable logic for local interlocks and automatic sequences
- Self-diagnostics with a watchdog, and health status reported to the control centre
- Remote configuration and firmware update, with authentication
- Local display and maintenance port for commissioning
- Operation from the station battery, with EMC immunity suited to a switchyard
Communication
Between the control centre and the posts, the link is usually optical fibre along the route, with a second path as backup.
- IEC 60870-5-101 on serial channels and IEC 60870-5-104 on TCP/IP networks
- Optical fibre as the main channel, with a standby channel on a separate path
- Continuous channel monitoring, with automatic switching and an alarm on failure
- Polled and spontaneous transmission, so that a status change is reported at once
- Time synchronization of RTUs from the control centre or from a local GPS receiver
- Communication statistics for each RTU and channel
Engineering
The complete design and development of a device, from concept or specification to a product ready for manufacture.
How a project runs
Every design stage has a test stage that answers it. The requirement written at the start becomes the acceptance test at the end, and the architecture decides what the integration tests must prove. We plan both sides together, so the test plans exist before the hardware does. You can enter at the top with only a concept, or bring a finished specification and start further down.
Requirements and concept
A protection device is specified by standards, by the purchaser's technical specification and by the manufacturer's own cost and size targets. We read all three and turn them into one set of requirements that can each be tested.
The architecture follows from budgets, not preferences. An operating time of a cycle or so has to be divided between filtering, decision and the output contact. An accuracy class has to be divided between the input transformer, the converter and the algorithm.
Stage output: requirement specification, clause-by-clause compliance matrix, architecture document, function design specification (FDS) and project plan.
Requirement capture
- Study of the governing specification: RDSO, utility or customer
- Applicable IEC and IS standards identified for each function
- Clause-by-clause compliance matrix, with deviations raised early
- Each requirement numbered, so it can be traced to a design item and a test
Architecture and budgets
- Channel count for analog inputs, binary inputs and output contacts
- Sampling rate and converter resolution against the accuracy class
- Operating time budget across filter, decision and output
- Partitioning between processor, DSP and FPGA
- Memory budget for settings, events and disturbance records
- Power and thermal budget for the enclosure
Feasibility and risk
- Component selection for a long production life and second sources
- Target cost estimate from a preliminary bill of materials
- Technical risks listed, with the experiment or prototype that will retire each one
Hardware design
Protection hardware has to measure a load current of a fraction of an ampere and a fault current of many times rated, on the same input, and still be accurate at both. It then has to survive for years beside switchgear, on a station battery, in heat, dust and electrical noise.
The design is planned around that environment from the first block diagram, and every circuit is analysed for its worst case before it is laid out.
Stage output: schematics, bill of materials, worst-case and derating analysis, hardware design description and hardware test specification.
Analog acquisition
- CT inputs for 1 A and 5 A secondaries, with thermal withstand for fault current
- Wide dynamic range, so that low load current and high fault current are both measured accurately
- PT inputs with isolation and surge protection
- Anti-alias filtering matched to the sampling rate
- Simultaneous sampling of all channels, so that phase relationships are preserved
- Factory calibration of gain and phase for each channel, stored in the device
Binary inputs and outputs
- Opto-isolated inputs for station DC voltages, with defined thresholds and debounce
- Output relays rated for trip coil duty: make, carry and break
- Trip circuit design that fails safe and avoids false operation on a single component failure
- Watchdog contact that signals an internal failure
Processing, power and communication
- Processor, DSP or FPGA platform with non-volatile storage and a battery-backed clock
- Wide-range power supply for DC and AC auxiliary voltages, with hold-up through supply dips
- Isolated RS-485, copper and fibre Ethernet, and a front service port
- Display, keypad and indication LEDs on the front panel
Reliability engineering
- Component derating and worst-case tolerance analysis
- Thermal analysis of the board in its enclosure
- Failure mode and effects analysis on the trip path and the power supply
- Reliability prediction from the bill of materials
- Enclosure, terminals and mounting designed with the manufacturer's mechanical team
PCB design
Board design is done by the same team, alongside the schematic and the firmware. Whether a relay passes its surge, fast transient and insulation tests is largely decided in the layout, long before the test laboratory.
The board is divided into field-side, measurement and logic areas, with defined isolation barriers between them and a planned path for every disturbance current to leave the board without crossing sensitive circuits.
Stage output: layout database, fabrication and assembly files, assembly drawings, and a layout review report.
Insulation and EMC
- Creepage and clearance distances for the insulation and impulse levels of IEC 60255-27
- Isolation barriers between field-side circuits and internal logic
- Surge and transient protection placed at the point of entry
- Grounding and shielding scheme designed for the whole product, not board by board
- Separation of switching power circuits from measurement circuits
Signal and power integrity
- Layer stack-up and controlled impedance for Ethernet and memory interfaces
- Low-noise routing and guarding of analog measurement paths
- Power distribution and decoupling for processors and converters
- Thermal relief and copper area for parts that dissipate heat
Manufacturability
- Design for manufacture: footprints, spacing, panelization and fiducials to suit the assembler
- Design for test: test points and programming access for production
- Conformal coating areas defined for humid and polluted sites
- Design rule checks, peer review and three-dimensional fit check with the enclosure
Firmware
A relay's firmware is a hard real-time system. Sampling must happen at exact intervals and the protection calculation must finish inside a fixed cycle, every cycle, while the same processor also talks to SCADA, drives the display and writes records to memory.
We structure the firmware in layers, so that the protection kernel can be tested on a PC against simulated signals and then run unchanged on the hardware.
Stage output: source code under version control, software design description, unit test results, static analysis report and release notes for each build.
Architecture
- Board support layer: boot loader, drivers and hardware abstraction
- Real-time operating system, with protection given the highest priority
- Protection kernel on a fixed, deterministic execution cycle
- Separate tasks for communication, HMI and record storage, so they cannot delay a trip
Device functions
- Settings management with setting groups, range checks and integrity checks
- Programmable logic for inputs, outputs and LEDs
- Time-stamped event log, fault records and disturbance records in non-volatile memory
- Communication protocol stacks and time synchronization
- Password levels for viewing, settings and control
- Firmware update through an authenticated boot loader
Self-supervision
- Continuous checks of memory, program integrity, converter reference and supply rails
- Hardware and software watchdogs
- Defined safe state on an internal failure: outputs blocked and the watchdog contact operated
Software quality
- Coding standard based on MISRA C, enforced by static analysis
- Peer review of every change before it is merged
- Unit tests for protection elements, run automatically on each build
- Version control and a traceable build for every release
PC and control centre software
The device is only as usable as the software an engineer uses to set it, test it and read its records. We write that software as part of the same project, so it stays in step with the firmware.
Stage output: installer, user guide and source code for each tool.
- Settings tool: read, edit, compare and download settings, online or from a file
- Retrieval of events, fault records and disturbance records
- Waveform viewer for COMTRADE records, with phasor, harmonic and impedance-locus views
- Live measurement and status displays for commissioning
- Logic editor for inputs, outputs and LEDs
- Firmware upgrade and calibration tools for the factory
- Control centre software for SCADA.
Algorithms
What a relay, recorder or fault locator does is decided by its algorithms. Each one is formulated mathematically, modelled, and tested against simulated and recorded faults before any firmware is written.
The firmware implementation is then checked against the model with the same test signals, so that what runs in the device is known to be what was designed.
Stage output: algorithm description, simulation model, test vectors and a characterization report of accuracy and operating time.
Measurement
- Fundamental phasor estimation by Fourier and cosine filtering
- Removal of the decaying DC component from fault current
- Frequency measurement and tracking, so that accuracy holds off nominal frequency
- Harmonic measurement, including second and fifth harmonic for restraint
- Sequence components, power, energy and rate of change of frequency
- Detection of CT saturation
Protection elements
- Impedance measurement with memory polarization for close-in faults
- Zone characteristics: parallelogram, quadrilateral and mho
- Biased differential characteristics with harmonic restraint and blocking
- Inverse-time curves to IEC 60255-151, and definite-time stages
- Delta-I vector-change detection for traction
- Thermal models for overload and negative phase sequence
- Fault location, including the AT neutral current ratio method
Modelling and validation
- Models in MATLAB and Simulink
- Fault and load cases from power system simulation, including traction load and inrush
- Replay of recorded COMTRADE disturbances
- Fixed-point implementation compared sample by sample with the model
- Measured operating time, accuracy and transient overreach for each element
Verification and validation
Before a prototype goes to an outside laboratory, it goes through our own test bench. A failure found here costs a day. The same failure found during type testing costs a laboratory slot and weeks.
Stage output: test procedures, test reports traced back to each requirement, and a list of open issues with their status.
Functional testing
- Secondary injection tests of every element: pickup, drop-off, timing and characteristic shape
- Dynamic tests with replayed fault waveforms
- Accuracy checked across the temperature range and the auxiliary supply range
- Logic, interlock and scheme tests with the binary inputs and outputs
- Protocol tests against master station simulators and third-party devices
Pre-compliance and endurance
- Pre-compliance EMC checks: fast transient, surge and electrostatic discharge
- Insulation and impulse checks on the prototype
- Temperature cycling and long-duration soak under load
- Supply interruption and brown-out tests
Regression
- Automated test sequences, repeated on every firmware release
- Every reported defect added to the regression set once fixed
Compliance testing support
A design is not finished until it passes. We prepare the test plan, go to the laboratory with the manufacturer, diagnose anything that fails and correct the design, until the type test report is complete.
For railway equipment we support the prototype tests required for approval against the RDSO specification. For utility equipment we support type testing at accredited laboratories to the purchaser's specification.
Stage output: type test plan, test samples prepared with the right settings and firmware, and a technical file to accompany the manufacturer's application.
| Product standard | IEC 60255-1 common requirements for measuring relays and protection equipment |
|---|---|
| Functional standards | IEC 60255-121 distance, 60255-151 overcurrent, 60255-127 voltage, 60255-181 frequency, 60255-149 thermal and 60255-187-1 differential protection |
| Product safety | IEC 60255-27: dielectric, impulse voltage, insulation resistance, protective bonding and clearances |
| EMC | IEC 60255-26: electrostatic discharge, radiated and conducted immunity, fast transient, surge, damped oscillatory wave, power frequency magnetic field, DC supply dips and ripple, and emission |
| Mechanical | IEC 60255-21: vibration, shock, bump and seismic |
| Environmental | IEC 60068-2: cold, dry heat, damp heat steady state and cyclic, and change of temperature |
| Enclosure | IEC 60529 degree of protection |
| Communication | Protocol conformance for IEC 60870-5 and IEC 61850, and interoperability with the purchaser's SCADA |
| Acceptance | Factory acceptance tests (FAT) and site acceptance tests (SAT) with the end customer |
Handover for manufacture
We do not manufacture. At the end of a project the manufacturer receives everything needed to build, test and support the product in its own factory, and we stay with the first batches until production is stable.
Stage output: the complete design package below, released under document control with a single revision level.
Design package
- Schematics, PCB layout and fabrication files
- Bill of materials with approved alternates and critical-part notes
- Firmware, as source or as released binaries, with version history
- PC software with installer
- Mechanical, front-panel and labelling drawings
Production test
- Production test procedure, with pass limits for every step
- Test jig design and test software
- Calibration procedure and calibration software
- Burn-in specification
Documents and transfer
- User manual, commissioning guide and technical data sheet
- Training for the manufacturer's production, testing and service staff
- Engineering support through the pilot batch and first production lots
Sustaining a design in production
A relay design stays in production for many years, and over that time components go obsolete, specifications are amended and field experience comes back. The same team maintains designs that are already in production, whether or not we designed them originally.
- Component lifecycle monitoring and replacement of obsolete parts
- Firmware maintenance releases, with regression testing before each one
- Root-cause analysis of field returns
- Updates for amendments to RDSO and utility specifications
- Feature enhancement and new variants from an existing platform
- Cost reduction through redesign of the bill of materials
- Migration of an older product to a current processor platform
- Assessment of what must be re-tested after a change
How we manage a project
You work directly with the engineers on your project, from the first discussion to the handover. That keeps the development transparent and leaves no room for the design to drift from what you asked for.
- Stage gates with a formal design review at the end of each stage, attended by the customer
- Requirement traceability from specification clause to design item to test result
- Configuration management of hardware, firmware and documents
- Documented change control once a baseline is agreed
- Issue tracking that the customer can see
- Regular progress reports against the agreed milestones
- Confidentiality and ownership of the design agreed in writing at the start
What We Design
Relays, fault locators, SCADA, battery chargers and recording equipment for traction and utility networks, designed for the companies that manufacture them.
We design. Our customers manufacture.
Emdescol is a design house. We do not manufacture or sell equipment.
Equipment manufacturers come to us for the design: the hardware, the PCB, the firmware, the algorithms and the software. They build the product, take it through approval and sell it under their own name. Everything on this page is equipment we design and develop for them.
Numerical relays for 25 kV traction
The relay types that make up the protection of a traction substation, as laid down in RDSO's specifications for traction substation protection.
| Feeder protection relay | Three-zone distance protection with parallelogram characteristic. Instantaneous overcurrent. Two-stage definite-time overcurrent. Wrong phase coupling. PT fuse failure. Switch on to fault. Multi-shot auto-reclose, with bypass on high-current faults. Local breaker backup. |
|---|---|
| Transformer protection relay | HV and LV side protection. Instantaneous overcurrent. IDMT overcurrent. Three definite-time overload stages. Restricted earth fault on each side. Alarm inputs for oil temperature, winding temperature, Buchholz and low oil level. |
| Transformer differential protection relay | Biased differential. Second-harmonic blocking for inrush. Fifth-harmonic restraint for over-excitation. Trip inputs for Buchholz, pressure relief device, oil temperature and winding temperature. |
| Delta current protection relay | Delta-I detection of high-resistance faults from the vector change in current. Second and third harmonic restraint against inrush and locomotive load. |
| Panto flash-over protection relay | Detection of a pantograph bridging a live and a dead section at an insulated overlap. Line PT indications. Trip circuit supervision. |
| Capacitor bank protection relay | Overcurrent. Current unbalance between the halves of the bank. Over voltage and under voltage. |
| Capacitor bank switching relay | Overcurrent protection combined with automatic switching of the capacitor bank in and out. |
| Wrong phase coupling relay | Standalone detection of two supply phases bridged across a neutral section, from the angle between voltage and current. |
| Bay control unit | Control, interlocking, measurement and status for one bay at a TSS, SSP, SP or ATP, with the interface to the RTU. |
| Supply monitoring relay | Supervision of the DC station battery supply and the AC auxiliary supply, with under and over voltage alarms and trip. |
Numerical relays for 2 x 25 kV AT traction
The AT feeding system has its own protection specification, covering the traction substation and the SSP, SP and ATP along the route.
| Scott-connected transformer protection | Differential protection matched to the Scott connection. Restricted earth fault. Overcurrent on the primary and on the 2 x 25 kV side as backup to the feeder relays. Auxiliary relays for transformer faults. |
|---|---|
| V-connected transformer protection | The same protection set, with the differential element matched to the V connection. |
| OHE protection, catenary and feeder | Directional three-zone distance protection with polygonal characteristic. Delta-I fault-selective protection. Instantaneous overcurrent. Under-voltage protection against wrong phase coupling. Two-shot auto-reclose. |
| Autotransformer protection | Differential protection for each 55 kV autotransformer. Auxiliary relays for autotransformer faults. |
| Bus bar protection | High-impedance differential protection. |
| Shunt capacitor bank protection | Over voltage, under voltage, overcurrent and unbalance. |
| Sectioning and sub-sectioning post protection | Feeder and autotransformer protection for SP, SSP and ATP that are equipped with circuit breakers. |
Relays for transmission
Relays for lines, bus bars and transformers at 132 kV and above.
| Line distance protection relay | Multi-zone distance protection (21) with quadrilateral and mho characteristics. Teleprotection schemes. Power swing blocking. Switch on to fault. Fault location. |
|---|---|
| Line differential protection relay | Current differential (87L) between line ends over an optical fibre channel, with channel supervision and backup overcurrent. |
| Bus bar differential protection relay | Differential protection (87B) of the bus bar zone, with check zone and CT supervision. |
| Transformer differential relay with REF | Biased differential (87T) with second and fifth harmonic restraint, and restricted earth fault (64R) on each winding. |
| Auto-reclose and check synchronizing relay | Single-pole and three-pole auto-reclose (79), with dead-line and synchronism checks (25) before closing. |
| Directional earth fault relay | Directional earth fault (67N) for high-resistance faults that distance elements do not see. |
| Over-fluxing relay | Volts-per-hertz protection (24) for transformers and generators, with inverse-time and definite-time stages. |
Relays for generation
| Multifunction generator protection relay | One relay carrying the generator's main protection elements, including differential, negative phase sequence, reverse power, over-fluxing, voltage, frequency and backup overcurrent. |
|---|---|
| Generator differential relay | Biased differential protection (87G) of the stator winding. |
| Negative phase sequence relay | Protection against unbalanced loading (46), with a thermal model of rotor heating. |
Relays for distribution and industry
Relays for 33 kV and 11 kV feeders, industrial plants and auxiliary supplies, in standard and miniature housings.
| Overcurrent and earth fault relay | Three overcurrent elements and one earth fault element (50, 51, 50N, 51N), with instantaneous, definite-time and IDMT characteristics. |
|---|---|
| Directional overcurrent and earth fault relay | Directional elements (67, 67N) for parallel feeders, ring mains and feeders with a source at both ends. |
| Sensitive earth fault relay | Low-set earth fault detection for high-resistance faults on overhead lines. |
| Feeder relay with auto-reclose | Overcurrent and earth fault protection with built-in multi-shot auto-reclose (79) for overhead feeders. |
| Frequency and df/dt load-shedding relay | Under and over frequency (81) and rate of change of frequency, in several stages for load shedding. |
| Motor protection relay | Thermal overload, locked rotor, unbalance, earth fault and limitation of the number of starts. |
| Under and over voltage relay | Under voltage, over voltage, or both in one unit (27, 59), with definite-time delay. |
| Phase failure and phase unbalance relay | Loss of a phase, phase unbalance and phase sequence on three-phase supplies. |
| Reverse power flow relay | Directional detection (32) of power flowing back into the source. |
| Overcurrent and current unbalance relay | Overcurrent with detection of unequal currents between phases or branches. |
Auxiliary and supervision relays
| Trip circuit supervision relay | Continuous monitoring of the trip coil and its wiring, with the breaker open and closed. |
|---|---|
| DC earth fault and battery monitoring relay | Detection of earth leakage on either pole of the station DC supply, and supervision of battery voltage. |
| PT fuse failure relay | Detection of a blown voltage transformer fuse, to block the elements that depend on voltage. |
| Automatic voltage regulating relay | Control of the transformer on-load tap changer to hold the bus voltage, with line drop compensation and parallel operation. |
What every relay has in common
Whatever the protection function, a numerical relay for a traction substation is expected to record, communicate and check itself.
- Fault waveform recording with pre-fault and post-fault data
- Time-stamped event log and fault records
- Live display of voltage, current and impedance
- Password-protected settings in fine steps, with setting groups
- RS-485 and Ethernet ports, with IEC 60870-5-103 or IEC 61850 to the RTU
- Continuous self-supervision with a watchdog contact
- Low burden on the CT and PT
Automatic fault locator (AFL)
On a 25 kV section, the reactance measured at the substation gives the distance directly. On a 2 x 25 kV section it does not, so the AFL uses the autotransformers themselves.
A fault between two autotransformers draws current through both of their neutral connections. The nearer the fault is to one of them, the larger that one's share. The ratio of the two neutral currents gives the position inside the AT cell.
- AT neutral current ratio, also called the boost-up current ratio method, for 2 x 25 kV sections
- Reactance method for conventional 25 kV sections
- Acquisition units at the TSS, SSP, ATP and SP, sampling at the same instant
- Identification of the faulted AT cell, then the distance within it
- Fault type: catenary to earth, feeder to earth or catenary to feeder
- Up line and down line distinguished on double-line sections
- Correction for the measured characteristic of each section
- Result in kilometres, sent to the RCC through the SCADA system
SCADA
We design both ends of the system and the link between them: the control centre software and the remote terminal units. Traction is the main focus, with the RCC and the RTUs at every TSS, SSP, SP and ATP, and the same platform serves utility control centres.
- Dual redundant servers, front-end processors, LAN and communication channels
- Militarized and de-militarized zones separated by firewalls
- Mimic displays, supervisory control, alarms, events, trends and reports
- Traction functions: automatic fault localization, feed extension, power blocks and maximum demand
- Utility functions: IEC 61850 gateway, load despatch link and load shedding
- Modular RTUs with one-millisecond event time stamping and relay gateway
Advanced battery chargers
Every relay, breaker trip coil and RTU in an unattended traction substation runs from the 110 V station battery. If the battery is not healthy, none of the protection works. The charger is therefore part of the protection system, and we design it as one.
- Automatic float-cum-boost charging for 110 V battery banks
- Constant-voltage and constant-current control with current limiting
- Microcontroller-based regulation with low output ripple
- Automatic changeover between float and boost from the battery's state
- Alarms for mains failure, charger failure, DC under and over voltage, and DC earth leakage
- Battery voltage, charging current and charger status available to the RTU for the RCC
- Built for unattended sites and for the supply variations found at traction substations
Disturbance recorders
After a trip, the question is what the network and the protection actually did. A disturbance recorder keeps a continuous buffer of every channel and freezes it around the event, so the pre-fault, fault and post-fault periods can all be examined.
- Analog channels for voltages and currents
- Digital channels for starts, trips and breaker status
- Triggers on digital edges, thresholds and rate of change
- Configurable pre-fault and post-fault recording time
- Time-stamped records, synchronized to an external clock
- Records in COMTRADE format for use in standard analysis tools
Phasor equipment
A phasor measurement gives the magnitude and the phase angle of a voltage or current against a common time reference. Compared across locations, the angles show how the network is behaving, which magnitudes alone cannot.
- Synchrophasors of voltage and current
- Frequency and rate of change of frequency
- GPS time synchronization
- Phasor data streaming to IEEE C37.118
Communication protocols
Each link in a protection and control system has its own protocol. We implement all of them.
| IEC 60870-5-101 and 104 | Telecontrol between the RCC and the RTUs, over serial channels and over TCP/IP networks |
|---|---|
| IEC 60870-5-103 | Numerical relays to the RTU: events, measurands and disturbance data |
| IEC 61850 | Substation automation over Ethernet, including client-server reporting and GOOSE messaging |
| MODBUS RTU and TCP | Battery chargers, meters, auxiliary devices and third-party equipment |
| IEEE C37.118 | Synchrophasor data from phasor equipment |
Specialized and custom devices
Some requirements are not met by any standard product: an unusual measurement, a protection function for one particular installation, or a replacement for equipment that is no longer made. We design and develop these to the customer's specification, using the same end-to-end process as our other equipment.
Products
Software tools and protocol libraries from Emdescol, built from the same engineering that goes into the equipment we design.
We do not manufacture equipment, but we do license our own software. These three products came out of our design work: the tools we needed on our own bench, and the protocol code that runs inside the devices we design.
EMDESWAVE
COMTRADE file viewer for analysing disturbance and fault records.
EMDESCOM
Multi-channel communication logger for COM, UDP and TCP/IP links.
Protocol libraries
Portable libraries for the protocols used in protection and SCADA.
EMDESWAVE
COMTRADE file viewer
After a trip, the record in the relay is the only witness. EMDESWAVE opens that record and lets a protection engineer see exactly what the voltages, currents and relay signals did, measure it, and report it.
Illustration of the layout, not a screenshot.
Open any record
- COMTRADE 1991, 1999 and 2013 formats (IEEE C37.111, IEC 60255-24)
- ASCII and binary data files
- Separate CFG, DAT, HDR and INF files, and the single-file CFF form
- Records from any make of relay or recorder
- Primary or secondary values, from the CT and PT ratios in the file
See and measure
- Analog and digital channels on a common time axis
- Zoom, pan, overlay and rearrange channels
- Two cursors with time difference, instantaneous, RMS and peak values
- Phasor diagram at the cursor, with magnitude and angle
- Harmonic spectrum and total harmonic distortion
- Frequency and sequence components
Analyse and report
- Impedance locus on the R-X plane, with relay zones overlaid
- Calculated channels from formulas on measured ones
- Views suited to single-phase traction records
- Several records side by side, aligned in time
- Export to CSV, image and printable report
- Save as a different COMTRADE version or sampling rate
EMDESCOM
Multi communication logger for COM, UDP and TCP/IP
When a relay will not talk to an RTU, the fastest way to find out why is to watch the bytes. EMDESCOM logs several serial ports and network connections at once, on one time axis, and decodes what it sees.
Illustration of the layout, not a screenshot.
Channels
- Several COM ports at once: RS-232, RS-485 and RS-422 through adapters
- UDP sockets, unicast and broadcast
- TCP client and TCP server connections
- All channels on one millisecond time axis
- Baud rate, parity, data and stop bits set for each port
Log and decode
- Hexadecimal and ASCII views, with direction marked
- Decoding of MODBUS, IEC 60870-5-101, 103 and 104, and DNP3 frames
- Checksum and CRC verification on every frame
- Response time and inter-frame gap measurement
- Parity, framing and timeout errors flagged
- Filters, search and colour for each channel
Test and record
- Pass-through mode between two ports or connections, to monitor a live link
- Send frames by hand, on a timer or from a script
- Triggers on a byte pattern: mark, alert or stop the log
- Long-duration logging to file, with rotation
- Statistics for each channel: frames, bytes and errors
- Export to text and CSV for test reports
Protocol libraries
Portable protocol stacks for protection, substation and SCADA
A manufacturer adding a protocol to a relay, an RTU or a gateway can spend a year writing and proving the stack. Ours are already running in the devices we design. We license them as ready-to-integrate libraries, with the support to bring them up on your platform.
| IEC 60870-5-101 | Controlling and controlled station. Balanced and unbalanced transmission. Process information, commands with select-before-operate, clock synchronization and file transfer. |
|---|---|
| IEC 60870-5-103 | Master and slave for protection equipment. Time-tagged messages, measurands, general interrogation, generic services and disturbance data transfer. |
| IEC 60870-5-104 | Client and server over TCP/IP. Multiple connections and redundancy groups. The same application layer as 101. |
| IEC 61850 | MMS server and client with reporting, logging and control. GOOSE publisher and subscriber. Sampled Values. Configuration from SCL files. |
| MODBUS | RTU, ASCII and TCP. Master and slave. Standard function codes and user-defined register maps. |
| DNP3 | Outstation and master, over serial and TCP/IP. Unsolicited responses, time synchronization and event buffering. |
| IEEE C37.118 | Synchrophasor data: PMU-side data, configuration and header frames, and the receiving side for a concentrator. |
Built for embedded targets
- Written in ANSI C, with no dependence on a particular compiler
- Operating system abstraction layer: bare-metal, RTOS, embedded Linux and Windows
- Small memory footprint, with static memory allocation available
- Hardware access through a thin serial and socket interface that you supply
What you receive
- API reference and integration guide
- Example applications for each role
- PC-based simulator of the opposite side, for testing your device
- Test suite covering the stack's functions
Support and licensing
- Integration support from the engineers who wrote the stack
- Customization for a purchaser's profile or interoperability list
- Help through conformance and interoperability testing
- Updates as the standards are amended
- Licence terms agreed for each product line
Want to try one?
Write to us for a demonstration, an evaluation copy or licence terms.
Technology
The standards, platforms and tools we design with, from current digital substation technology to the legacy platforms still in service.
| Telecontrol and relay protocols | IEC 60870-5-101, 103 and 104, DNP3, MODBUS RTU and TCP, IEEE C37.118 synchrophasors |
|---|---|
| Digital substation | IEC 61850 Edition 2: MMS client-server, GOOSE and Sampled Values on the process bus (IEC 61850-9-2, IEC 61869-9), with SCL-based engineering |
| Network redundancy | PRP and HSR to IEC 62439-3, for zero-time recovery on station and process bus, and RSTP |
| Time synchronization | IEEE 1588 PTP with the power utility profile (IEC 61850-9-3), IRIG-B, SNTP and GPS |
| Cyber security | IEC 62351 and IEC 62443 practices: role-based access, TLS-secured communication, secure boot, signed firmware and security event logging |
| Processing platforms | ARM Cortex-M and Cortex-A processors, multi-core DSPs, FPGAs and SoC FPGAs that combine a processor with programmable logic, alongside MIPS and Intel MCS-51 for legacy designs |
| Measurement front end | Simultaneous-sampling 16-bit and 24-bit ADCs, high sampling rates for harmonic and transient capture, and low-power instrument transformer inputs |
| Operating systems | Real-time operating systems for protection tasks, and embedded Linux for communication, HMI and gateway functions |
| Power electronics | High-frequency switch-mode conversion with digital control, and silicon carbide and gallium nitride devices for battery chargers |
| Communication interfaces | 100 Mbit and gigabit Ethernet on copper and optical fibre, RS-232/485/422, USB and USB-OTG |
| Remote monitoring | 4G LTE and NB-IoT links, MQTT and OPC UA for condition monitoring data, with GSM, GPRS, RF, Wi-Fi, Bluetooth and Zigbee |
| Peripheral buses | I2C, SPI, GPIO, CAN 2.0B, LIN |
| Display and HMI | Colour TFT and touch screens, browser-based HMI served from the device, graphical and dot matrix displays |
| Storage | Solid-state and flash memory for event and disturbance records, USB drives |
| Simulation and testing | MATLAB and Simulink modelling, real-time hardware-in-the-loop testing, COMTRADE playback through secondary injection, LabVIEW |
| Hardware design tools | OrCAD Capture, OrCAD PCB Editor, PADS, PSpice, with signal integrity and thermal analysis |
| Software | C and C++ for firmware, C# and .NET, Java and Python for PC and control centre software, MPLAB and Visual Studio |
| Databases | Oracle, Microsoft SQL Server, MySQL and PostgreSQL, with time-series storage for telemetry history |
About Emdescol
More than 20 years of designing the equipment that protects railways and power grids.
When a fault strikes a 25 kV catenary or a 220 kV line, a relay has a few thousandths of a second to recognise it and act. For more than two decades, our work has been making sure it does, every time, and never when it should not.
A design house for the hardest part of the power system
Emdescol designs and develops protection, control and monitoring equipment for railway traction and power utilities. Manufacturers build and sell it under their own names. The engineering inside is ours.
This is work that very few organizations take on from end to end. A protection relay is small, but it holds a precision measuring instrument, a real-time computer, a set of mathematical algorithms and a safety-critical trip circuit, and it must pass some of the most severe type tests applied to any electronic product. Most companies can do one or two of those things well. We have spent more than 20 years learning to do all of them together.
The result is a record of complex designs taken from a blank page through type testing and approval, into production, and into service on live networks, with a precision that has earned the confidence of the manufacturers and engineers who depend on them.
Everything inside the enclosure
A numerical relay looks like one product. It is really several engineering disciplines that have to agree with each other inside a few milliseconds. We design every block in this chain, which is why the blocks fit.
A rare combination, built over two decades
Protection equipment sits where three fields meet. Engineers who are expert in one seldom speak the language of the other two. Our team was built to hold all three.
Power system engineering
We understand the network before we design for it: fault behaviour, traction load, transformer inrush, CT saturation, autotransformer feeding, and the protection philosophy the purchaser expects.
Embedded systems
We design the electronics and the real-time firmware: precision analog measurement, isolated inputs and outputs, deterministic protection cycles and hardware that survives a switchyard.
Communication systems
We implement the protocols that connect a device to the rest of the system, from a serial link to a relay up to a redundant, secured SCADA control centre.
What 20 years of this work teaches
Security matters as much as dependability
A relay that fails to trip is a disaster. A relay that trips when it should not stops trains and blacks out feeders, and it happens far more often. We design and test for both, and we treat load, inrush and harmonics as seriously as faults.
The type test is decided on the drawing board
Surge, fast transient and impulse results are fixed by the schematic and the layout. We design for the laboratory from the first block diagram and prove the prototype on our own bench first, so our customers do not pay for repeat test slots.
A design has to live for twenty years
Equipment we design stays in service for decades. We choose components for long availability, document every decision, and keep supporting a design long after it has gone into production.
The model and the device must agree
Every algorithm is proven in simulation, and then the firmware is checked against that model sample by sample. What runs in the field is exactly what was designed.
Newer systems reward those who study them early
We took up the 2 x 25 kV autotransformer system, digital substation standards and SCADA security while they were still new to the industry here. Our customers now draw on that head start.
Why manufacturers trust us with their products
Your product, your name
We stay behind the scenes. The design is developed for you, in confidence, and goes to market under your brand.
One point of accountability
Hardware, firmware, algorithms and software come from one team. When something needs fixing, there is no one else to point at.
Engineers you can talk to
You deal directly with the people doing the work, from the first discussion to the handover, and you see progress as it happens.
With you after handover
We support the first production batches, the type tests and the years of maintenance releases that follow.
The team and the design centre
Our engineers are selected and mentored for this field specifically. They cover power system studies, analog and digital hardware, PCB design, real-time firmware, algorithms, protocols and PC software, and they sit together, so the person writing a distance element can talk to the person who designed the CT input stage it measures through.
The founders have spent more than 20 years designing hardware and embedded software for leaders in the power industry, and that experience sets the standard for every project.
Our design and development centre in Bengaluru is equipped with the instruments, development tools and test equipment the work demands, from secondary injection and waveform replay to pre-compliance checks on prototypes.
Bring us the design others find too difficult
Tell us what the device must do and which specification it must meet. We will show you how we would get it there.
Team
The people behind the equipment, and what they have been up to.
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Team activities
Careers
Join the engineers who design the hardware, firmware and algorithms inside relays, recorders and RTUs.
Contact
Tell us about the relay, device or system you want designed.
Head office
Emdescol Private Limited
No 28, 29, 1st Main Road, Prakruthi Layout,
Singapura, Vidyaranyapura (PO),
Bengaluru 560097, Karnataka, India
Development centre
Shree Ganga Dreams, Ground Floor,
882, M.E.S. Ring Road, Muthyala Nagara,
Opposite to Mother Theresa Public School,
Bengaluru 560054, Karnataka, India