The MVH relays is an inverse time volts/hertz relay whose application is to protect generators and transformers from damaging overexcitation. Overvoltage, underfrequency, or a combination of the two can result in excessive flux density in the generator or transformer iron, producing heat that can reach damaging levels. Heating damage to the transformer or generator, if seere enough, can result in costly equipment outages.
Since the characteristic damage curves for various generator and transformer manufacturers differ, the protective relay has the capability to encompass a large number of settings and damage curves.
The MVH relay provides front panel switch selectable settings, enabling the user to select characteristics that best fit the equipment being protected. The microprocessor design provides automatic self-checking of the software, as well as indication for loss of dc battery voltage. The non-volatile memory provides retention of the microprocessor programs and tip indications.