Function Block; Functionality - ABB 615 series Technical Manual

Hide thumbs Also See for 615 series:

Table of Contents

Protection functions

Function block

GUID-A65D073B-32BA-45B6-9881-77C146EA64F6 V1 EN

Function block

The multifrequency admittance-based ground-fault protection function 67YN provides

selective directional ground-fault protection for high-impedance grounded networks, that

is, for compensated, ungrounded and high resistance grounded systems. It can be applied

for the ground-fault protection of overhead lines and underground cables.

The operation of 67YN is based on multifrequency neutral admittance measurement,

utilizing cumulative phasor summing technique. This concept provides extremely secure,

dependable and selective ground-fault protection also in cases where the residual

quantities are highly distorted and contain non-fundamental frequency components.

The sensitivity that can be achieved is comparable with traditional fundamental frequency

based methods such as IoCos/IoSin (67/51N, 67/50N), Watt/Varmetric (32N) and neutral

admittance (21YN).

67YN is capable of detecting faults with dominantly fundamental frequency content as

well as transient, intermittent and restriking ground faults. 67YN can be used as an

alternative solution to transient or intermittent function 67NIEF.

67YN supports fault direction indication both in operate and non-operate direction, which

may be utilized during fault location process. The inbuilt transient detector can be used to

identify restriking or intermittent ground faults, and discriminate them from permanent or

continuous ground faults.

The operation characteristic is defined by a tilted operation sector, which is universally

valid for ungrounded and compensated networks.

The operating time characteristic is according to the definite time (DT).

The function contains a blocking functionality to block function outputs, timers or the

function itself.

1MAC059074-MB A

615 series ANSI

Technical Manual

Table of Contents