VAE-430 vs CMC 356: Which Relay Test Set Fits Your Test List?

The VAE-430 and the OMICRON CMC 356 are both secondary-injection relay test sets, but they are built for different test lists. The CMC 356 gives six independent current channels, 300 V phase-to-neutral outputs and native IEC 61850. The VAE-430 gives three current channels at 40 A (120 A in parallel), four voltage channels, twenty software modules included and a US$2,000 price. Choose on channels and protocol, not on brand.

OMICRON and CMC 356 are trademarks of OMICRON electronics GmbH. Figures for the CMC 356 below are taken from published manufacturer data and should be checked against the current datasheet before a purchase decision. VA-TEK is not affiliated with OMICRON.

What is the short answer?

If your test list is three-phase protection – overcurrent, distance, directional, zero-sequence, underfrequency, synchronism, reclosing – the VAE-430 does the work at US$2,000 per set with the software included. If you must inject six currents simultaneously, drive 300 V phase-to-neutral, or test IEC 61850 at the process bus, you need a six-channel set: the CMC 356, or the VAE-660 at a lower capital cost with three-phase voltages capped at 120 V.

The comparison in one table

Where the CMC 356 is still the reference

Three cases keep the CMC 356 on the shortlist, and none of them is marketing.

1. Six currents at once. Transformer differential with vector-group compensation, busbar protection with six or more CT circuits, and generator split-phase schemes need six independent current sources in one shot. The VAE-430 cannot do it; the VAE-660 can.
2. 300 V phase-to-neutral. Electromechanical relays and some high-burden static relays need more voltage than the 120 V L-N outputs of the VAE-430 and VAE-660 provide. If your relay list includes them, check the burden before you buy anything.
3. Process-bus testing. Sampled values and GOOSE require a native IEC 61850 client with the appropriate licence. The VAE-430 offers no native 61850 client; the test is done through binary I/O and analog injection instead, which is a different test.

There is a fourth, commercial case: when a utility acceptance procedure or an OEM commissioning manual names the CMC 356, the instrument becomes part of the contract. That is a procurement constraint, not a technical one, and no datasheet argument will remove it.

Where the VAE-430 is enough

Most field-commissioning work is three-phase. The VAE-430 was specified for that list:

• Overcurrent, directional overcurrent, zero-sequence overcurrent and directional zero-sequence
• Distance and impedance characteristic tests, with an R-X plane and automatic zone verdict
• Undervoltage and underfrequency load shedding, including df/dt blocking
• Synchronism check, auto-reclosing, breaker-failure and trip-circuit supervision
• Transformer differential with harmonic restraint – for a two-winding transformer, in single-phase or three-phase steps
• Harmonic and DC tests with true RMS and fundamental separation

Two details matter more than the headline current: 40 A per phase is above the 30 A or 32 A of most six-channel sets, and the parallel mode reaches 120 A single-phase for high-burden CT circuits. The voltage ceiling of 120 V L-N is the real limit – not the current.

What a spec sheet will not tell you

Four things decide whether a set survives a commissioning season, and none appears in a comparison table:

• Calibration evidence. Ask what the certificate covers, who issues it, and what a recalibration costs and takes. A cheap set with an expensive or slow calibration loop is not cheap.
• Software licensing. A per-module licence model means the set you buy is not the set you need six months later. Confirm exactly which modules are included and what an upgrade costs.
• Operator time. A test that takes four manual steps instead of one costs engineer hours on every job. Ask for a live demonstration against your own test list, not a product video.
• Support in your language and time zone. A field failure during an outage is measured in hours. Check the response path before you sign, not after.

Price, delivery and software licensing

The VAE-430 is US$2,000 per set EXW, delivery in 7 days for a standard configuration, with all twenty test modules on one PC application and no per-module licence. The interface runs in nine languages – English, Simplified Chinese, Korean, Russian, Italian, French, Spanish, Portuguese (Brazil) and Japanese – which matters when the commissioning crew changes country between projects.

A six-channel CMC 356 configuration is quoted by OMICRON and its distributors; the total depends on the channel options and on how many Test Universe modules you license. Compare the fully licensed total, not the base instrument, and add the recalibration cost over the years you intend to keep it.

Which set fits which test list?

Frequently asked questions

Can the VAE-430 replace a CMC 356?

For three-phase secondary-injection tests, yes – overcurrent, distance, directional, zero-sequence, frequency and reclosing all run on the VAE-430. It cannot replace a CMC 356 where six currents must be injected simultaneously, where more than 120 V phase-to-neutral is required, or where IEC 61850 is tested natively.

Does the VAE-430 support IEC 61850?

Not natively. There is no built-in sampled-values or GOOSE client. Digital-station testing is done through the relay’s binary inputs and outputs, or by pairing the set with an external 61850 test tool. If process-bus testing is a routine part of your scope, plan for that tool in the budget.

How much does a CMC 356 cost?

OMICRON quotes per configuration, and the total depends on channel options and on the Test Universe modules you license. Ask for a fully licensed price that includes the modules you will actually use, and add recalibration over the ownership period, before comparing it with any other set.

I have a three-winding transformer. Can I use three current channels?

Not for a simultaneous differential test. A three-winding scheme needs six currents at once – three per side for the two sides under test. The VAE-660 provides six current and six voltage channels with 8 DI / 8 DO for that case.

Is the VAE-430 software licensed per module?

No. All twenty modules – three-phase AC, DC, AC/DC, harmonic, state sequence, distance, differential, differential harmonic, relay timing, group tests, COMTRADE playback and the rest – ship with the instrument on one PC application.

Next step

Before you ask for a quotation, run the rent-or-buy break-even – for a single outage the answer is often to rent the class of instrument first.

Send us the relay families and the test items you run in a typical commissioning season. We will map them against the VAE-430 module list and tell you honestly where a six-channel set is required – including when that set should not be ours.