ABB SPAU 140 C Synchro-check relay

SPAU 140 C

Synchro-check relay

The relay incorporates two identical stages

which operate as independent units. Both stages

of the synchro-check relay has two parallel func

tions: a synchro-check function and a voltage

check function.

The synchro-check relay can be used for two

different operating conditions, the most typical

of which is where both sides of the circuit

breaker to be closed are live. Then synchronism

is always checked before the circuit breaker is

given the permission to close. The other situa

tion is where one or both sides of the circuit

breaker to be closed are dead and, consequently,

frequency and phase difference cannot be meas

ured. In this case the relay checks the energiz

ing direction. The user is able to define the volt

age range within which the measured voltage is

determined to be "live" and "dead".

The purpose of the synchro-check function is

to find the instant when the voltages on both

sides of the circuit breaker are in synchronism.

The conditions for synchronism are met when

the voltages on both sides of the circuit breaker

have the same frequency, are in phase and are of

such a magnitude that the concerned busbars

or lines can be regarded as live.

When the frequency, phase angle and voltage

conditions are fulfilled, the duration of the syn

chronizing conditions is checked so as to en

sure that they will still be met when the con

tacts of the circuit breaker close. This duration

is determined on the basis of the frequency and

phase difference measured. Depending on the

circuit breaker and the closing system, the de

lay from the moment the closing signal is given

until the circuit breaker finally closes is about

50 - 250 ms. The CB operate time selected tells

the relay for how long, at least, the conditions

have to persist.

The voltage-check function checks the energiz

ing direction. Energizing is defined as the situ

ation where a dead network part is connected

to an energized section of the network. The con

ditions of the network sections to be controlled

by the circuit breaker, i.e. which side has to be

live and which side dead, are determined by set

ting. A situation where both sides are dead is

possible as well.

When the energizing direction corresponds to

the settings, the situation has to be constant for

a certain time before the close signal is permit

ted. The purpose of this operate time (dead time)

is to make sure that the dead side remains

deenergized and that the situation is not due to

a temporary interference. Should the conditions

not persist for the specified operate time, the

operate time is reset and the procedure is started

again when allowed by the conditions. Not un

til the required energizing situation has been

constant throughout the set operate time, cir

cuit-breaker closing is permitted

Measured voltage U1. rated voltage 100 V

Measured voltage U1. rated voltage 110 V

Measured voltage U2. rated voltage 100 V

Measured voltage U2. rated voltage 110 V

Measured voltage U3. rated voltage 100 V

Measured voltage U3. rated voltage 110 V

The relay is able to measure either phase-to-phase voltages or phase-to-neutral

voltages, but phase-to-phase voltages are preferred.

Stage 1 of the synchro-check relay can be blocked by applying an external auxiliary

voltage level blocking signal BS to terminals 10-11. The blocking function is se

lected with switch 1 of switchgroup SGB in the main menu of the relay. The

blocking function is not activated in the default setting of the relay.

Stage 2 of the synchro-check relay can be blocked by applying an external auxiliary

voltage level blocking signal BS to terminals 22-23. The blocking function is se

lected with switch 2 of switchgroup SGB in the main menu of the relay. The

blocking function is not activated in the default setting of the relay.

When command mode operation has been selected for stage 1. the stage is acti

vated for CB closing by an auxiliary voltage level control signal CS13. applied to

the terminals 45-46.  If  continuous mode operation has been selected no control

signal need be applied to the relay. Switch 3 of switchgroup SGB is used for select

ing the desired mode of operation. Default setting of stage 1:  continuous mode

operation.

When command mode operation has been selected for stage 2. the stage is acti

vated for CB closing by an auxiliary voltage level control signal CS23. applied to

the terminals 47-48.  If  continuous mode operation has been selected no control

signal need be applied to the relay. Switch 4 of switchgroup SGB is used for select

ing the desired mode of operation. Default setting of stage 2:  continuous mode

operation.

At command  mode operation the alarm signal for failed circuit breaker closing

(NC13 and NC23) and for CB close request signals that have remained activated

(CSF13 and CSF23) is received via output relay A at command mode operation.

The switches 1. 3. 5 and 7 of switchgroup SGR are used for the configuration of

the alarm signals. No alarm signals are received at continuo