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IL04915001E

 

 

 

Effective 7/09 

 

Instructions for D64RPB30 Series C1 Ground Fault Relay 

 
 

S1

1
2
3
4
5
6
7
8

O

N

1
2
3
4
5
6
7
8

O

N

2 = S/C
4 = CT

F

2

0

2

4

-0

1

-0

1

2

4

-2

4

0

V

A

C

 /

 D

C

C

T

N

.C

.

N

.O

.

DOUBLE CLICK
FOR TEST

T

FLASHES:
1 = E/F
3 = BACKUP
5 = F/S CV LOSS
CONT’ = TRIP FAILED
& OTHER

2 = S/C
4 = CT

RATINGS PER IEC 60755:
In
I n
F

= SEE EACH CT MAX.
= 0.03 - 9 A
= 45 - 450 Hz

Cat. No.  
D64RPB30

 

Figure 1. D64RPB30 Ground Fault Relay 

 

1. FUNCTIONALITY 
1.1 Ground fault current sensing and fault 
reporting 

The D64RPB30 is a microprocessor based 
ground fault relay for use on solidly grounded or 
resistance grounded systems. 
The D64RPB30 employs an external 500:1 
current transformer (CT) to measure ground 
fault current flowing to ground in electrical power 
distribution systems. The measured value is 
compared against two setpoints. The lower one, 
the Ground fault (G/F) setpoint, is settable from 
30 mA to 9 A in 8 steps and has an associated 
delay settable from 20 ms to 10 s in 6 steps. The 
higher one, the Short Circuit (S/C) setpoint is 
fixed at 125 A. When the current exceeds the 
G/F setpoint for the set delay, but does not 
reach the S/C level, a ‘G/F’ is diagnosed and the 
unit trips by operating its internal relay. Should a 
fault occur causing a ground fault current 
exceeding the S/C setpoint, the D64RPB30 
operates its relay without any delay diagnosing 
an ‘S/C’. 

 
 
Optionally, the user can select the operation of 
the relay to be Type 2 Coordinated with an 
upstream tripping device (fuse or breaker) to 
protect any local contactor contacts in the case 
of S/C faults. In this case the unit does not trip 
initially when the measured current exceeds the 
S/C setpoint, but waits for the upstream device 
to take care of current interruption and then 
trips. The latter trip flags the location of the fault 
to the user and also allows him to instantly re-
close the upstream tripping device. Should the 
upstream device fail to perform, then automatic 
backup protection makes the D64RPB30 trip -as 
a last resort- 20 ms or 300 ms, selected by 
dipswitch, after the S/C occurred. 
 
The relay contacts can be used in a trip or alarm 
circuit. Form “Z”, normally open and normally 
closed contacts is provided. 
 
The D64RPB30 is a Class A device as defined 
in the IEC 60755 standard; therefore it is 
designed for operation with sinusoidal AC and 
pulsating DC currents. 

1.2 External CT supervision 

With any G/F protection scheme using an 
external CT, there is an inherent risk that ground 
faults will not be detected because of a bad or 
deteriorated connection to the CT. Both open 
circuits and shorts on the CT connection will 
prevent detection. Therefore, the conventional 
practice is to prove correct tripping regularly by 
means of current injection. This is an annoying 
procedure disrupting normal plant operation. 
 
The D64RPB30 solves this problem by 
constantly supervising the connection to the 
external CT. Open circuits as well as shorts are 
detected and will cause a trip. 
 
Please note that the D64RPB30 does not 
employ any DC injection to implement this 
feature. Even small DC currents sent through 
the secondary of a CT can bias its core enough 
to shift the trip point outside specification on 
sensitive settings. 

Summary of Contents for Cutler-Hammer D64RPB30 Series

Page 1: ...l contactor contacts in the case of S C faults In this case the unit does not trip initially when the measured current exceeds the S C setpoint but waits for the upstream device to take care of curren...

Page 2: ...failed alarm state is As a result the red LED will now show the original cause of the trip 1 4 Reset Test pushbutton The built in momentary pushbutton is used to verify the condition of the D64RPB30 i...

Page 3: ...ontrol voltage is removed the relay will issue a 0 2 0 3 second pulse This means that when control voltage is restored after a trip due to loss of control voltage the contact will remain open This avo...

Page 4: ...ans that there is no electrical isolation between the control voltage input and the internal electronics As a result these share a common ground reference This reference is applied to the system throu...

Page 5: ...stalled beside the unit to act as the chassis ground point Use a minimum 14 AWG stranded conductor 6 For good EMC behavior it is important as in any installation to run all wiring especially if unshie...

Page 6: ...voltage 1 week minimum until the memory is read by pressing the Reset button Ground fault circuit G F Trip Level settable 0 03 0 10 0 50 1 2 3 5 9 A Accuracy of trip point 15 0 of Trip Level 3 G F Tri...

Page 7: ...8 A2 28 mm 1 1 inner diameter External CT Supervision circuit CT loop resistance causing a fault O C 1 k CT shunt resistance causing a fault S C 50 CT Fault Trip Delay 1 5 s Relay contacts Configurati...

Page 8: ...magnetic compatibility EMC for industrial process measurement and control equipment Part 4 2 Electrostatic discharge ESD immunity EN 61000 4 3 Electromagnetic compatibility EMC for industrial process...

Page 9: ...OURCE CURRENT CARRYING NEUTRAL WHEN USED GROUNDED SYSTEMS 1 Phase 2 wire 1 Phase 3 wire 3 Phase 3 wire 3 Phase 4 wire LOAD FIGURE 2 D64RPB30 TYPICAL FIELD CONNECTION WITH EXTERNAL 500 1 CURRENT TRANSF...

Page 10: ...1 38 35 2 36 60 2 76 70 1 38 35 Mounting hole Dia 0 22 5 5 DIN Rail Release 4 03 103 4 95 126 Dimensions Figure 3 Dimensions Drawing Approximate Dimensions in Inches mm Table 2 Approximate Dimensions...

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