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Effective:
December 1996
Supersedes I.L. 41-252. Dated April 1987
( | ) Denotes Change Since Last Issue
!
CAUTION
It is recommended that the user become
acquainted with the information in this instruc-
tion leaflet before energizing the equipment. Fail-
ure to observe this precaution may result in
damage to the equipment.
1.
APPLICATION
The type SRW relay is a single phase directionally
controlled timing relay used to protect ac generators
from motoring. When such a condition occurs and
persists for a predetermined time interval, the gener-
ator may be tripped or an alarm sounded. The SRW
may also be used to sense lagging power factor load
flow in an abnormal direction as shown in
The directional unit has 30 degree maximum sensitiv-
ity characteristics. The timer unit is adjustable from 2
to 21.5 seconds, .2 to 2 seconds or 2 to 63 seconds
depending upon relay style. The range of the current
pickup settings is from 1 mA to 40 mA at the maxi-
mum sensitivity angle.
2.
CONSTRUCTION
The SRW relay consists of three printed circuit mod-
ules and a front panel packaged in a FT-11 case. For
detailed information on the flexitest case, refer to I.L.
41-076.
The photograph in
Figure 1
its case.
All possible contingencies which may arise during installation, operation or maintenance, and all details and
variations of this equipment do not purport to be covered by these instructions. If further information is
desired by purchaser regarding this particular installation, operation or maintenance of this equipment, the
local ABB Power T&D Company Inc. representative should be contacted.
Printed in U.S.A.
ABB Power T&D Company Inc.
Power Automation and Protection Division
Coral Springs, FL 33065
Figure 8.
shows the SRW relay in
SRW
Reverse Power Relay
with Adjustable Timer
2.1. Interface Module
The interface module, mounted at the bottom of the
relay, contains a voltage transformer, a current trans-
former, a reed relay and two miniature high power
relays. This module also contains a dc power supply
and its dropping resistors.
(1)
DC Power Supply — Three dc input voltages,
48, 125 and 250 volts, can be selected by con-
necting a jumper to a suitable position which is
printed on the PC board's left-hand side. The
relay is shipped with a setting of 125 volts.
(2)
Voltage Transformer — This transformer con-
sists of one primary winding and one second-
ary winding. The continuous voltage rating at
primary side is 150% of the rated line voltage
but the relay's accuracy is designed between
30% and 110%. The secondary voltage is fed
to the SRW module as a phase angle refer-
ence.
(3)
Current Transformer — this is a two-winding
transformer with a turns ratio of 20 to 400. A
load resistor of 20 ohms is connected across
the secondary winding. The secondary voltage
is linearly proportional to the primary current if
the input current is less than 5 amps. For cur-
rent higher than 5 amps, the secondary volt-
age is clamped to approximately peak-to-peak
voltage of 20 volts in order to void ct satura-
tion.
(4)
Trip Relays — Two miniature high power
relays are connected to the trip circuit. Each
relay is equipped with a normally open contact
Instruction Leaflet
41-252A
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Table of Contents
Related Manuals for ABB SRW
Summary of Contents for ABB SRW
- Page 1 150% of the rated line voltage ator may be tripped or an alarm sounded. The SRW but the relay’s accuracy is designed between may also be used to sense lagging power factor load 30% and 110%.
-
Page 2: Theory Of Operation
Reed relay and reset switch — The reed relay 2.3. Transformer In-rush Module is for monitoring and indication of the actual The In-rush module is located on top of the SRW trip current flow. The trip current should be module and electrically connected by two bottom between 0.5 and 30 amperes. - Page 3 I.L. 41-252A × ∑ . The voltage circuit (Vac) contains three sections. -- - I nφ 1. Phase shifter which shifts the input voltage n = 2 by -150 degree. 2. Sine-wave to square wave inverter (180 degree shift), i.e., the waveform at point This means that the waveform at point F contains a C leads the signal at point A by +30 degree.
-
Page 4: Circuit Description
Q101 and pick up two telephone will jump from -15V to +15V and change the bias relays SRW-1 and SRW-2. If a trip current is voltage at pin 5 from -2V to +2V. For |V | < 2V, a detected by the SRW-1 contact and reed relay RR, constant voltage will be at pin 7, either +15V or -15V. -
Page 5: Installation
Set the 10-position thum- It is recommended that a performance check be applied to the SRW relay to verify that the circuits are bwheel switch to provide the next lowest available functioning properly. The SRW test diagram shown pickup value. - Page 6 11 (c). Repeat step #6 but for the current +35 deg. between 1 and 40 mA. 5. Connect a scope to pin 7 of IC5 on the SRW C. Pickup Setting module. A square wave should be seen. Reduce the input ac voltage to 36 ±4 Vac.
-
Page 7: Routine Maintenance
I.L. 41-252A 6. Set the timer switches at 1 sec. settings and times of operation should be checked at least once every year or at such other intervals as 7. Turn on SW-1 suddenly. The digital timer may be indicated by experience to be suitable to the should read between 0.96 and 1.080 sec- particular application. -
Page 8: Renewal Parts
I.L. 41-252A (a) Connect the test circuit as shown in Figure (2 sec.). 11(c). (c) Turn on ac and dc voltages. Set the input (b) Set the p/u thumbwheel switch to #7 and current at 1 ampere and adjust the phase apply ac, dc voltages and ac current of 40 shifter for current leading voltage by +30 deg. - Page 9 Test Connection for the SRW Relay ..........1495B54 Outline and Drilling Plan for the SRW Relay in the Type FT-11 Case ....57D7900...
- Page 11 I.L. 41-252A * Sub 3 9645A75 Figure 2: Simplified Terminal Connection Drawing Denotes Change...
- Page 12 * Sub 2 1495B44 Figure 3: SRW Block Diagram Denotes Change...
- Page 13 * Sub 4 1355D79 Figure 4. Internal Schematic – SRW Relay (Sheet 1 of 2) Denotes Change...
- Page 14 * Sub 4 1355D79 Figure 4a. Internal Schematic – SRW Relay (Sheet 2 of 2) Denotes Change...
- Page 15 I.L. 41-252A * Sub 2 1500B50 Figure 5: Component Location - SRW Module Denotes Change...
- Page 16 I.L. 41-252A * Sub 4 1500B49 Figure 6: Component Location – Interface Module Denotes Change...
- Page 17 I.L. 41-252A * Sub 3 1499B41 Figure 7: Component Location – In-Rush Module Denotes Change...
- Page 19 * Sub 3 1495B46 Figure 9: External Schematic of the SRW Relay to Prevent Reverse Magnetization When Utility Tie is Removed from the Local System. Denotes Change...
- Page 20 I.L. 41-252A Sub 1 9645A93 Figure 10: Multiplier Waveforms...
- Page 21 I.L. 41-252A Sub 2 1495B54 Figure 11: Test Connection for the SRW Relay...