Table of Contents
Advertisement
Monitoring is enabled by setting the scheme switch [TCSPEN] to "ON" or "OPT-ON" and the two
BIs selected "TCFAIL". When "OPT-ON" is selected, the monitoring is enabled only while CB is
closed. TCS by 2BIs should be applied BI1 and BI2 for BI inputs. The TCS by 2BIs set the BI
threshold voltage ([BITHR1]) as about the half of trip supply voltage. If the trip supply voltage is
110V (or 24V) , [BITHR1] sets "48" (or "12").
+ve
Trip
Supply
Resistor
The resistors connected in series with the binary inputs are to prevent unnecessary tripping of the
circuit breaker if any one component suffers a short-circuit condition. The value of resistance should
be chosen to limit the current flowing through the circuit breaker trip coil to 60mA in the event of a
short circuit of BI1 with the circuit breaker closed. A typical value for a 110V dc rated circuit is
3.3kΩ.
3.3.4 Circuit Breaker Monitoring
The relay provides the following circuit breaker monitoring functions.
Circuit Breaker State Monitoring
Circuit breaker state monitoring is provided for checking the correct condition of the circuit breaker
(CB) in accordance with the position of its auxiliary switches. If two binary inputs are programmed
to the functions 'CB CONT OPN'(CBOPN) and 'CB CONT CLS'(CBCLS), then the CB state
monitoring function becomes active. In normal circumstances these inputs are in opposite states.
Figure 3.3.4 shows the scheme logic. If both show the same state during five seconds, then a CB
state alarm CBSV outputs and "Err:CB" and "CB err" are displayed in LCD message and event
record message respectively.
The monitoring can be enabled or disabled by setting the scheme switch [CBSMEN].
CB CONT_OPN
CB CONT_CLS
Normally open and normally closed contacts of the CB are connected to binary inputs BIm and BIn
respectively, and functions of BIm and BIn are set to "CBOPN=ON" and "CBCLS=ON". (Refer
to Section 4.2.6.8.)
GRE110
Trip Output
Binary Input
(BI1)
Figure 3.3.3 Trip Circuit Supervision by 2 binary inputs
=1
[CBSMEN]
"ON"
+
Figure 3.3.4 CB State Monitoring Scheme Logic
72
Circuit Breaker
CB Aux.
CB Trip Coil
Contacts
Binary Input
(BI2)
t
1
&
5.0s
6 F 2 T 0 1 7 2
-ve Trip
Supply
0
1271
CBSV
- Quick Links:
- Inverse Time Overcurrent Protection
Hide quick links:
Advertisement
Table of Contents
