VA Technology 
A relay test set is specified by the schemes it has to prove, not by the size of its datasheet. Three questions decide the purchase: how many current channels the protection schemes demand, how much power each channel can push into the relay burden, and whether the instrument has to run stand-alone at the panel. Get the channel count wrong and no software update repairs it.
VA-TEK builds two machines for this work. The VAE-430 is a three-phase set for overcurrent, directional, distance and frequency schemes. The VAE-660 offers six current and six voltage channels for schemes that need every end injected at once.
Start with the protection schemes in scope
Channel count follows the scheme list. Feeder overcurrent, directional and frequency protection are three-phase work: three currents and three voltages, injected one loop at a time. Distance protection adds zone and reach checks but still fits a three-phase source for phase-to-earth and phase-to-phase loops.
Differential schemes spanning more than one end are the step up. Transformer, generator, busbar and line differential protection compares currents from two or more locations, and the test has to reproduce that comparison with every end live at once. Six current channels let both windings, or both line ends, carry current simultaneously.
Both machines sit in the secondary test instruments family, and the tests that follow selection are covered in the secondary injection testing guide.
Three-phase or six-phase relay test set
The two configurations differ in more than channel count. The table compares the figures that matter at the panel.
| Specification | Three-phase (VAE-430) | Six-phase (VAE-660) |
|---|---|---|
| Current channels | 3 x 0-40 A AC | 6 x 0-30 A AC |
| Single-phase parallel output | 1 x 0-120 A at 900 VA | 1 x 0-180 A at 1000 VA |
| Per-phase power | 420 VA at 40 A | 300 VA at 30 A |
| Voltage channels | 4 x 0-120 V AC | 6 x 0-120 V AC |
| Weight | 22 kg | 20.3 kg |
| Typical schemes | Overcurrent, directional, distance, frequency | Multi-winding differential, busbar, line differential |
| Typical user | Commissioning and maintenance crews | Protection laboratories, multi-ended schemes |
Why per-phase power decides high-burden work
Current range is the headline figure; per-phase power is the working one. The current coil of an electromechanical relay can draw several tens of volt-amperes at its setting. A source that holds 30 A into a light coil may collapse into a heavy one, and pickup and timing results then read low.
The VAE-430 puts 420 VA on each current channel at 40 A. The VAE-660 puts 300 VA per channel at 30 A, but 1000 VA when all channels are paralleled into a single phase at 180 A. Three-phase high-burden work follows the per-phase figure; single-element high-current tests follow the parallel figure.
Both machines hold an AC accuracy of 0.2 percent or better, which is what a numerical relay with a tight pickup tolerance needs.
Portability and stand-alone operation
Both sets are built for mobility. The VAE-430 weighs 22 kg in a 400 x 300 x 180 mm case; the VAE-660 weighs 20.3 kg in a 470 x 550 x 280 mm case. The six-phase machine is the lighter of the two.
Stand-alone operation removes the laptop. The VAE-430 runs a built-in operating system with an LCD and local control, with a serial port for PC-driven test plans. The VAE-660 embeds a PC with 2 USB ports and 1 serial port, so a full test can be executed and stored at the panel.
Binary I/O should match the scheme logic. The VAE-430 provides 8 binary inputs and 4 binary outputs; the VAE-660 provides 8 inputs and 8 outputs for schemes with more trip and blocking contacts. The VAE-430 and the VAE-660 both cover these steps; the choice usually settles on the differential schemes in the list.
Frequently asked questions
Do I need six phases for transformer differential protection?
Six current channels are needed when both windings, or every end of a line, must carry current at the same time. That is the condition the relay meets during a through-fault or an internal fault. A three-phase set covers single-ended differential checks on smaller transformers and the overcurrent elements behind them, and is the practical choice when the scheme list stops there.
Can one test set cover electromechanical and numerical relays?
Yes, within limits. An AC accuracy of 0.2 percent or better suits numerical relays, and high per-phase power drives the heavier coils of electromechanical relays. Both machines inject through analog current and voltage inputs. Process-bus testing over IEC 61850 with sampled values and GOOSE is a different interface and needs dedicated digital test equipment.
What does high burden mean for a relay test set?
Burden is the load the relay’s current coil presents to the source, in volt-amperes. An electromechanical relay with a heavy burden can draw far more than a numerical relay at the same setting current. A set with 420 VA per channel holds its setting into that load; a low-power source collapses.
The commissioning sequence around this decision is set out in the protection relay commissioning checklist.
Selection of a relay test set comes down to the scheme list, the burden of the relays on it, and how the instrument is used. A scheme list can be sent through the request a quote form for a configuration check, and the contact page reaches the specification team.
