
23
Fig. 10 shows a substation, in which the protec-
tion and control functions are based on feeder
terminals type SPAC 531 C and SPAC 533 C.
For clarity reasons other protection relays have
been omitted.
Applications
In the example in Fig. 11 the protection of the
outgoing feeders and the control of the circuit
breakers are based on the feeder terminal SPAC
531 C1. This version is a fully equipped unit
including overcurrent and short circuit protec-
tion, directional earth fault protection and a
control module.
A feeder terminal type SPAC 531 C3 is used for
protecting the incoming feeder cubicle and the
busbar system and for controlling the circuit
breakers. This version includes a three-phase
overcurrent module and a control module. The
operation of the busbar protection equipment is
blocked by the starting signals of the overcur-
rent modules of the outgoing feeders.
The protection of the high voltage side of the
power transformer and the control of the circuit
breaker have been implemented using a SPAC
533 C feeder terminal which includes a dual-
stage overcurrent and a dual-stage earth fault
protection module, a harmonics measuring
blocking module and a control module. When
starting the overcurrent relay of the low voltage
side blocks the high-set stage of the HV side
overcurrent relay.
The feeder terminals of the SPAC 530 series can
be used both in one-breaker systems and in two-
breaker systems. The examples 1 to 5 describe
different protection methods and situations in
one-breaker systems. Example 6 shows a basic
two-breaker system.
The operation of the feeder terminal SPAC 531
C1 used in a two-breaker system is the same as
that of a SPAC 531 C1 used in a one-breaker
system, except for certain contact functions.
Fig. 10. Substation protection and control using SPAC 530 series feeder terminals. Other
protection relays and the connection of the remote control system have been omitted.
SPAC 533 C
SPAC 531 C3
(Example 5)
Ι
3
>>
Ι
3 >
Ο ↔ Ι
U
0
U
0
SPAC 531 C1
(Examples 1,2 ja 3)
U
0
SPAC 531 C1
(Example 4)
Ι
3
>>
Ι
3 >
Ο ↔ Ι
Ι
Ο → Ι
Ι
3
>>
Ι
3 >
Ο ↔ Ι
Ι
Ο → Ι
Ι
3
>>
Ι
3 >
Ο ↔ Ι
Ι
Ι
3
>>
Ι
3 >
Ο ↔ Ι
Ι
SPAC 531 C1
(Examples 1,2 ja 3)