Relay Test Set as a Programmable V/I Source
A protection relay test set is bought to test protection relays. Underneath the protection vocabulary it is a programmable multi-phase voltage and current source with a precision timer, binary inputs and binary outputs. That is the part that transfers to other test objects: an ATS controller, a generator controller, a reactive power controller, a tap changer control, a DC relay or a fault recorder. This page explains the three ways the source is used, which non-relay applications hold up in practice, and where the instrument stops.
Four functions in one box
The instrument is not a signal generator with a case. Four functions have to be present at the same time before it can replace a scheme around a relay:
- A multi-phase programmable source. Three or six current channels and four or six voltage channels, with independent amplitude, phase and frequency, plus harmonic superposition.
- Precision measurement and timing. The instrument records what it generated and when a binary input changed state, so pickup, dropout and operating time can be read back.
- Binary I/O. Inputs read trip, alarm and status contacts; outputs emulate breaker auxiliary contacts, interlocks and remote signals.
- Test software organised around protection principles. State sequences, ramps, COMTRADE playback and report generation are what turn the hardware into a test.
Remove any one of the four and the remaining device is a signal source, a data logger or a bench supply. The combination is why the same instrument can test a feeder relay in the morning and an ATS controller in the afternoon.
Three ways to use the source
| Usage | What you emulate | Typical test object | What matters |
|---|---|---|---|
| CT/PT secondary signals | The voltage and current a protection or measurement device sees during normal load and faults | Protection relays, RTUs, bay controllers, fault recorders, grid-code relays | Channel count, phase and frequency accuracy, timing |
| Dual-source and generator signals | Two live three-phase supplies, a generator output, or a bus with a synch-check point | ATS/STS controllers, generator and paralleling controls, microgrid controllers | Six simultaneous voltage channels, state sequences, binary I/O |
| General programmable AC/DC source | A calibrated, adjustable voltage or current for a device that is not a protection relay | Relays, contactors, trip coils, transducers, panel meters, sensors | DC range, resolution, stability, harmonic content |
Ten non-relay applications
The list is ordered by how often the application is a real purchase rather than a technical possibility. “Strong” means customers already buy an instrument or outsource the work for this test alone.
| # | Application | What the source provides | Reality | Main limit |
|---|---|---|---|---|
| 1 | ATS / STS / transfer controllers | Two three-phase voltage sets, frequency and phase control, status I/O, timing | Strong | Dual-source test needs six voltage channels; VAE-430 has four |
| 2 | Generator and paralleling controllers | Three-phase V/I, frequency and phase, state sequences, breaker status I/O | Strong to moderate | Controller vendors sell dedicated simulators; third-party FAT and commissioning still need a flexible source |
| 3 | Reactive power and capacitor bank controllers | V/I with phase angle, harmonic superposition, switching outputs | Moderate, often underestimated | Tests the controller, not the capacitor bank main circuit, inrush or discharge |
| 4 | Tap changer controllers (ATCC) | V/I, phase, raise/lower outputs, blocking inputs | Moderate, narrow | Parallel operation needs more channels; the OLTC mechanism is a separate test |
| 5 | Transducers, panel meters and electricity meters | V/I, phase, frequency | Moderate, expanding with the 0.1 % AC specification | Not a 0.05 class standard; 0.2 class meter calibration needs a better source |
| 6 | DC relays, contactors and trip coils | Programmable DC voltage and current, binary timing | Moderate | ±160 V DC covers 24/48/110 V coils, not 220 V coils |
| 7 | Switchgear secondary control and interlocking | DC source, binary I/O, timing | Moderate | Does not replace mechanical characteristics, contact resistance or dielectric tests |
| 8 | Fault recorder and data recorder checks | COMTRADE playback, small-channel analog signals | Marginal | No IRIG-B, no large channel count, limited playback repeatability |
| 9 | Power quality and filter controllers | Harmonics 1–20, V/I, phase | Marginal | No flicker, interharmonics or high-frequency content; not a Class A power quality calibrator |
| 10 | 400 Hz aviation relay MRO | Frequency and V/I within the 0–1000 Hz range | Marginal | No aviation qualification, no load simulation; 115/200 V three-phase 400 Hz schemes need more than a signal source |
Teaching and forensic investigation are two further purchase reasons. The test object is still a relay, but the buyer is a university, a training centre, an insurer or an investigator. The technical use does not change; the documentation and the report do.
What decides the model
Count three things before choosing between the VAE-430 and the VAE-660: simultaneous sources, burden and binary I/O.
| Requirement | VAE-430 | VAE-660 |
|---|---|---|
| Current channels | 3 × 0–40 A; 1 × 0–120 A parallel | 6 × 0–30 A; 3 × 0–60 A; 1 × 0–180 A parallel |
| Voltage channels | 4 × 0–120 V AC; 1 × 0–240 V L-L | 6 × 0–120 V AC; 3 × 0–240 V L-L |
| Power per phase | 3 × 420 VA at 40 A; 4 × 80 VA at 120 V | 6 × 300 VA at 30 A; 6 × 80 VA at 120 V |
| Single-phase parallel output | 900 VA at 120 A | 1000 VA at 180 A |
| Binary I/O | 8 inputs / 4 outputs; 0.1 ms time resolution | 8 inputs / 8 outputs; ±1 ms |
| Dual-source ATS with live normal and emergency voltages | Sequential or single-source only | Yes, with six voltage channels |
| Generator or transformer differential 87G / 87T | Not with three current channels | Yes, six current channels |
| Weight | 18 kg | 21 kg |
The VAE-430 is the field and single-object instrument: feeder, motor, transformer overcurrent, DC relay, controller logic and teaching. The VAE-660 is the scheme instrument: two live sources, six-phase differential, generator protection and panel FAT where spare channels shorten the test.
Where the source stops
| Boundary | Why | What to use instead |
|---|---|---|
| 0.05 class standard source | Open-loop source; the recorded value is a set-point snapshot, not an independent measurement | A metrology standard source |
| 0.2 class meter calibration | AC 0.1 % gives a 2:1 test uncertainty ratio against a 0.2 class meter; 4:1 needs 0.05 % | A meter test set or a higher-accuracy source |
| IEC 61850 Sampled Values and GOOSE | Analog injection only; no process-bus interface | A dedicated digital substation test set |
| Primary injection and HV withstand | The instrument is a secondary signal source, not a power source | Primary injection set, HV test set |
| PMU compliance testing | No GPS/PTP/IRIG-B and no C37.118.1 test software | A PMU calibrator with time synchronisation |
| 220 V DC coils | Programmable DC output stops at ±160 V; the auxiliary supply is fixed 110/220 V | A dedicated DC source or the station battery |
| Inverter power stage and grid-code certification | Tests the protection relay or controller, not the converter | Certification test bench with a grid simulator |
Device application pages
- ATS and STS controller testing
- Generator protection testing
- Reactive power and capacitor bank controller testing
- Tap changer controller (ATCC) testing
- COMTRADE playback and fault forensics
- DC relay and trip coil testing
Industry application pages
- Data centers
- Industrial plants
- Renewable energy
- Panel builders and OEMs
- Marine and offshore
- Rail and metro
Frequently asked questions
Can a relay test set be used as a general lab source?
Yes, within its range. It is a programmable three- or six-phase AC source from 0 to 1000 Hz with DC outputs up to ±160 V and ±10 A, harmonic superposition and a precision timer. It is not a calibrated standard source and should not be used as the reference in a metrology chain.
Can it calibrate panel meters or transducers?
It can perform a functional check on 0.5 class and lower devices. With AC accuracy of 0.1 %, the test uncertainty ratio against a 0.5 class device is 5:1. Against a 0.2 class device it is 2:1, which is below the 4:1 margin most quality systems expect, so 0.2 class calibration needs a better source.
Does it test the controller or the equipment behind it?
The controller. It injects the voltages and currents the controller senses and reads the commands it issues. It does not operate the transfer switch under load, start the generator or switch the capacitor bank.
Can one instrument test an ATS and the generator protection in the same sequence?
Yes, on the VAE-660, if the channels and I/O are planned together. Six voltage and six current channels plus eight inputs and eight outputs keep the generator protection and the ATS status signals connected through the transfer sequence.
Does it support 50 Hz and 60 Hz?
Yes. The frequency range is 0–1000 Hz in PC mode. The VAE-430 local mode is limited to 20–300 Hz, so 16.7 Hz railway testing and other sub-20 Hz work must be run from the PC software.