PR120/V

What does this measuring module do?

This module is designed to add voltage measurement capability to compatible ABB Emax protection releases. It reads primary voltages, enables voltage- and power-related measurements, and supports additional protection functions that rely on voltage values.

Which protection releases is it used with?

It is used with ABB PR122/P and PR123/P electronic releases fitted to Emax air circuit breakers. In the documented range, PR120/V is optional with PR122/P and standard with PR123/P.

What extra measurements become available when this module is installed?

When fitted, the relay can provide voltage readings, power measurements, power factor, energy values and mains frequency. Depending on the circuit-breaker configuration, this can include line-to-line voltages, phase voltages, residual voltage, and active, reactive and apparent power values.

Can the module help power the relay?

Yes. The PR120/V can supply energy to the relay from busbar voltage, which allows the relay to operate even when there is no auxiliary supply, no load current, or the circuit breaker is open, provided the required voltage conditions are present.

What voltage range can it handle with direct connection?

The module can work with direct connection to the circuit-breaker bars for phase-to-phase voltages up to 690 V. For higher system voltages, operation is supported through an external voltage transformer, up to 1150 V.

When is a voltage transformer needed?

A voltage transformer is required for three-phase systems with rated voltage above 690 Vrms phase-to-phase. The documented arrangement calls for star/star or delta/delta configurations, with transformer performance between 10 VA and 20 VA inclusive.

What settings usually need to be configured after installation?

Typical settings include rated voltage, whether a voltage transformer is present, transformer primary and secondary voltages, power flow direction, and neutral enabling for certain three-pole arrangements. On PR123/P, additional signal-related parameters are also available.

Which protection functions rely on this module being installed?

Installing this module enables the relay to use voltage-based functions such as undervoltage, overvoltage, residual voltage, reverse active power, underfrequency, overfrequency and voltage unbalance monitoring. It is also required for certain residual current configurations used with an external Rc sensor and the correct rating plug.

What should be checked if voltage, power or power factor readings look incorrect?

The first points to check are the wiring between the voltage transformer and the module, and the voltage-related parameter settings in the relay. Incorrect transformer connection or incorrect voltage setup can lead to inaccurate voltage, power and power factor readings.

Does this module affect what can be viewed on the relay display?

Yes. With the PR120/V installed, the relay can display voltage and power pages in addition to current measurements. It also expands the available measurement and logging functions compared with a current-only configuration.

Can it be used for harmonic and waveform information?

Yes, but this depends on the release. With PR123/P, the measuring functions extend to waveform display and harmonic analysis when the PR120/V is present. This gives access to additional visibility of network voltages and phase currents.

Are there any installation limitations for the voltage wiring?

Yes. The documented maximum length for voltage transformer to PR120/V wiring is 15 metres, using shielded two-wire cable with the shield earthed at both ends. Keeping within these installation limits helps maintain reliable measurement performance.