Siemens SG8158-00 사용자 설명서

Protective Function Configuration

Siemens Energy & Automation, Inc.

 

 29

The 50BF Breaker Failure function can be enabled and dis-

abled (2801). When enabled, the protective function begins

monitoring the current flow in the circuit following a trip com-

mand by the relay. Simultaneously, the protective function

starts a timer. If the current flow does not drop below the

pickup value specified (2802) and before the set time delay

(2804) has elapsed, a breaker failure is assumed. At this

point, another trip command can be issued to a different

breaker (via a different output ocntact if available).

The condition of a breaker failure trip depend on the method

chosen, the value of the current after the time has run out,

and the position of the a and b switches.

The range of the pickup value (2802) is based on the sec-

ondary phase CT rating and is in secondary amperes. 

The time delay (2804) represents the time between pickup

and trip. The delay can be adjusted from 8 to 254 line cycles

of delay. The function operates if it remains in pickup for

longer than the time delay.

Breaker failure protection monitors the current flow only fol-

lowing a trip by the contact identified at address 1004 (see

Section 4.2). This is the contact matrixed to the overcurrent

protection. 

Breaker position is sensed through dedicated binary inputs

that monitor the 52a and 52b switches on the breaker mech-

anism (breaker mounted). The 52a and 52b switches have a

total of four possible position combinations which can be

decoded as illustrated in Table 5.3. The 52a and 52b

switches referred to are those which traditionally provide indi-

cation of circuit breaker position (52b) and trip coil continuity

(52a). All error reporting can be enabled and disabled, and

the actions to be taken are configurable. Refer to

Section 6.6.

2800 50BF Breaker Failure

Address Parameter

Option

2801 Function

Enabled or Disabled

2802 Pickup 

5 A CTs:  0.25-5 A

1 A CTs:  0.05-1 A

(0.01 A steps)

2804 Delay

8-254 cycles

2805 Check

current, breaker opened, 

current or breaker opened

Table 5.3 52a and 52b Switches Decoding

52a Switch 

Position

52b Switch 

Position

Condition Registered

Open

Open

Trip Coil Continuity Error, or 

Breaker Withdrawn

Open

Closed

Circuit Breaker Open

Closed

Open

Breaker Closed

Closed

Closed

Circuit Breaker Mechanism Error

Exceptions to the normal operating conditions include the

presence of push-to-test switches across either the

a-switch, b-switch, or both. A push-to-test switch across the

b-switch will produce a false indication of a breaker mecha-

nism error when the breaker is actually closed. A push-to

test switch across the a-switch (and hence across the trip

solenoid) will produce a false indication of a breaker mecha-

nism error when the breaker is actually closed.

The Breaker Mechanism function (8305), when enabled,

senses an error in the mechanism that controls the position

of one or both switches (breaker mechanism error), causes

an action to be taken, and an event to be logged if the

switches are ever both closed for more than 100 ms. No

other time delay is implemented. When this function detects

an error, it is considered to be in pickup until the condition is

no longer present. 

The ISGS relay considers the b-switch to be more reliable. If

it senses the switches both open at the same time, the

breaker is considered to have a trip coil continuity error or to

be withdrawn. The 52a switch closed and the 52b switch

open are interpreted as a closed breaker. If the relay senses

the  52a switch open and the 52b switch closed, the

breaker is considered to be open. Refer also to Table 5.3.

5.18 Demand Setpoints 

The ISGS relay is capable of activating outputs and sending

events when predefined demand calculations exceed the set

thresholds. These setpoints can be enabled or disabled and

are capable of activating any output. Measurement and set-

point parameters in address block 3100 set the alarm report-

ing threshold for the ISGS relay. 

The Demand Parameters function selects the time periods

for demand calculations performed by the relay and allows

the user to enable overcurrent demand and kilowatt demand

protection. 

Demand intervals (periods) are set to 15, 30, or 60 minutes

(3101). Demand calculations are updated at the end of every

demand period. 

Demand period calculations can begin on the hour or at any

quarter hour afterwards. The intervals are indicated as 0, 15,

30, or 45 minutes and are set in the Sync Time parameter

(3102). 

3100 Demand Parameters

Address Parameter

Option

3101 Demand Interval

15, 30, 60 minutes

3102 Sync Time

0, 15, 30, or 45 after hour

3103 Subperiods 60

1, 2, 3, 4, 6, or 12

3104 Subperiods 30

1, 2, 3, or 6

3105 Subperiods 15

1 or 3

3106 I Av Dmd Function

Enabled or Disabled

3107 I Av Dmd Pickup

0-9999 A (1 A steps)

3108 KW Dmd Function

Enabled or Disabled

3109 KW Dmd Pickup

0-999,999 kW (1 kW steps)

5

isv3o_1.bk : isv3opro.frm  Page 29  Wednesday, August 7, 1996  10:51 AM