GE EntelliGuard G - Adjustable Selective Instantaneous

DET-653C EntelliGuard
®
G Circuit Breaker Application Guide
24-May-12 Section 3. EntelliGuard
®
TU Trip Unit System
©2012 General Electric All Rights Reserved
22
Each of these Instantaneous trips provides optimum
protection, selectivity or both as required for different
applications, subject to the capabilities of the respective
circuit breakers in which the trip units are installed.
Adjustable Selective Instantaneous
The EntelliGuard TU uses an exclusive algorithm, developed
by GE, to recognize the wave shape of fault current within a
cycle. With the improved analysis of the fault current wave
shape, the trip unit allows the circuit breaker to trip
immediately yet provide superior selectivity when used
above current limiting circuit breakers or fuses. In many
cases, the trip unit’s Instantaneous pickup may be set quite
low yet allow for complete selectivity up to the circuit
breaker’s full withstand level. For a list of possible selective
combinations of GE circuit breakers employing the
EntelliGuard TU trip unit and various downstream
overcurrent devices, see GE publication DET-537.
The EntelliGuard TU trip unit can be furnished with one of
two Instantaneous adjustment ranges. The standard
adjustable range may be as high as 15X the trip plug value
on all UL 489 or UL 1066 circuit breakers. An optional
Extended Range Adjustable Selective Instantaneous, as high
as 30X, may be provided for UL 1066 Listed Low Voltage
Power Circuit Breakers (LVPCBs). LVPCBs also allow for this
adjustable Instantaneous trip to be turned off. The minimum
adjustable Instantaneous pickup setting for all circuit
breakers is 2X the trip plug rating. The available maximum
pickup settings are described in Table 3.10. The maximum
Instantaneous pickup is limited by the circuit breaker’s
withstand rating.
Table 3.11. Maximum Adjustable Instantaneous Pick-up for EntelliGuard G Circuit Breakers with Normal or Extended
Range Option
“In” (Plug
Rating, A)
Withstand Rating
42
50
65
85
100
Normal
Range
Extended
Range
Normal
Range
Extended
Range
Normal
Range
Extended
Range
Normal
Range
Extended
Range
Normal
Range
Extended
Range
150-2,000
15
N/A
15
N/A
15
30
15
30
15
30
2,200
N/A
N/A
15
N/A
15
28
15
30
15
30
2,400
N/A
N/A
15
N/A
15
25
15
30
15
30
2,500
N/A
N/A
15
N/A
15
24
15
30
15
30
3,000
N/A
N/A
15
N/A
15
20
15
26
15
30
3,200
N/A
N/A
N/A
N/A
15
19
15
25
15
29
3,600
N/A
N/A
N/A
N/A
15
17
15
22
15
26
4,000
N/A
N/A
N/A
N/A
15
15
15
20
15
23
5,000
N/A
N/A
N/A
N/A
N/A
N/A
15
16
15
19
6,000
N/A
N/A
N/A
N/A
N/A
N/A
13
N/A
N/A
N/A
The Adjustable Selective Instantaneous will clear a fault in
three cycles when used in 60Hz or 50Hz applications. Zone
Selective Interlocking (I-ZSI) may be used with this
Instantaneous function, allowing several breakers with
overlapping Instantaneous protection to be selective with
each other. Because each circuit breaker is set to trip
Instantaneously for faults within their respective zones of
protection, fast protection and selectivity are achieved
simultaneously.
The special selective Instantaneous algorithm allows any
circuit breaker above current limiting devices to be set with
a relatively low Instantaneous pickup and still achieve
significant selectivity. The system may be able to provide
Instantaneous protection for most faults, including high
impedance arcing fault, while maintaining significant levels
of selectivity. Figures 3.11 and 3.12 later in this document
demonstrate the performance of the Instantaneous ZSI
capability
.
Table 3.12. Time Current Curves
Breaker Type
TCC
EntelliGuard G: Selective
Instantaneous & RELT
DES-094
Power CB: Selective Instantaneous
& RELT
DES-101
Power Break: Instantaneous
DES-099
Power Break II: Selective
Instantaneous and HSIOC (Override)
DES-100