ABB Relion 670 Series Technical Reference Manual page 552

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Table of Contents

Voltage protection

Loss of voltage check LOVPTUV (27)

Function description

Loss of voltage check

Introduction

Loss of voltage check (LOVPTUV, 27) is suitable for use in networks with an

automatic system restoration function. LOVPTUV (27) issues a three-pole trip

command to the circuit breaker, if all three phase voltages fall below the set value for a

time longer than the set time and the circuit breaker remains closed.

Principle of operation

The operation of Loss of voltage check LOVPTUV (27) is based on line voltage

measurement. LOVPTUV (27) is provided with a logic, which automatically

recognizes if the line was restored for at least tRestore before starting the tTrip timer.

All three phases are required to be low before the output TRIP is activated. The

PICKUP output signal indicates pickup.

Additionally, LOVPTUV (27) is automatically blocked if only one or two phase

voltages have been detected low for more than tBlock.

LOVPTUV (27) operates again only if the line has been restored to full voltage for at

least tRestore. Operation of the function is also inhibited by fuse failure and open

circuit breaker information signals, by their connection to dedicated inputs of the

function block.

Due to undervoltage conditions being continuous the trip pulse is limited to a length set

by setting tPulse.

The operation of LOVPTUV (27) is supervised by the fuse-failure function (BLKV

input) and the information about the open position (CBOPEN) of the associated circuit

The BLOCK input can be connected to a binary input of the IED in order to receive a

block command from external devices or can be software connected to other internal

functions of the IED itself in order to receive a block command from internal

functions. LOVPTUV (27) is also blocked when the IED is in TEST status and the

function has been blocked from the HMI test menu. (Blocked=Yes).

identification

1MRK505222-UUS C

ANSI/IEEE C37.2

device number

Technical reference manual

Relion red670