Signals - ABB 615 series Technical Manual

Hide thumbs Also See for 615 series:

Table of Contents

Protection functions

The vector shift detection also protects synchronous generators from damaging due to

islanding or loss-of-mains. To detect loss-of-mains with vector shift function, the

generator should aim to export or import at least 5...10% of the generated power to the

grid, in order to guarantee detectable change in loading after islanding or loss-of-mains.

Multicriteria Loss of Mains

Apart from vector shift, there are other passive techniques which are used for detecting

Loss of Mains. Some of these passive techniques are over/under voltage, over/under

frequency, rate of change of frequency, voltage unbalance, rate of change of power and so

on. These passive methods use voltage and frequency to identify Loss of Mains. The

performance of these methods depends on the power mismatch between local generation

and load. The advantage of all these methods is that, they are simple and cost effective, but

each method has a non detectable zone. To overcome this problem, it is recommended to

combine different criteria for detecting Loss of Mains.

Two or more protection functions run in parallel to detect Loss of Mains. When all criteria

are fulfilled to indicate Loss of Mains, an alarm or a trip can be generated. Vector shift and

rate of change of frequency are two parallel criteria typically used for detection of Loss of

Chosen protection criteria can be included in the Application Configuration tool to create

multicriteria loss of mains alarm or trip.

Signals

78V Input signals

78V Output signals

Phase-to-ground voltage A or phase-to-phase voltage

Phase-to-ground voltage B or phase-to-phase voltage

Phase-to-ground voltage C or phase-to-phase voltage

Block signal for activating the blocking mode

Protection function internally blocked

1MAC059074-MB A

615 series ANSI

Technical Manual

Table of Contents