Effective 10/2004
Page 27
I.L. 70C1036H05
The setting range for UnderFrequency or OverFrequency
tripping and alarming is 48.0 to 52.0 Hz for a 50 Hz
System and 58.0 to 62.0 Hz for a 60 Hz System.
Table 4.1 includes two examples of the circuit breaker and
Relay A operation.
Voltage Unbalance is adjustable from 5 to 50% in steps of
1%. A difference between Max Phase and Min Phase
higher than the Voltage Unbalance setting, times Min
Phase Voltage, will activate the function.
4.2.2.4 Voltage, Frequency Relays A,B,C
Relay A, a normally open contact, can be mapped to an
Alarm condition, which can provide a real time contact
information of these parameters: UnderVoltage,
OverVoltage, UnderFrequency, OverFrequency and Voltage
Unbalance. Each alarm setting does have a separate time
delay adjustment.
The Phase Rotation Alarm can be set to ABC or CBA or
OFF in the Alarm menu.
(See Appendix D-16)
This setting
if encountered in application will generate an alarm condi-
tion. Phase Rotation Alarm can then be mapped to this
Relay A. With this contact an interposing relay with time
delay can be employed to provide time delay and contact
arrangements to interface with the circuit breaker’s closing
circuit (spring release coil) to either prevent closing or to
open the circuit breaker (Shunt Trip coil). Relay B and
Relay C can also be mapped to the Voltage or Frequency
TRIP. These include UnderVoltage, OverVoltage,
UnderFrequency, OverFrequency and Voltage Unbalance
Trip and Reverse Power Trip. In addition Relay B and
Relay C together will share a Manual or Auto Reset
selection. This is provided in the SYSTEM menu and will
provide means to reset the Relay B and Relay C associ-
ated contacts. The default setting is MANUAL reset. The
resetting of these is accomplished via the Reset
pushbutton. The AUTO Reset setting will automatically
reset these two relays within five seconds after the trip
event.
The Phase Rotation setting should be programmed in the
Alarm menu to alarm when the Digitrip encounters this
Phase Rotation setting.
Table 4.1 Examples of the Circuit Breaker and Relay A Operation Versus Frequency
EXAMPLE 1
(Assumes line to line voltage > 84V)
ProGRam SETting
SYSTEM FREQ
60Hz
VOLTAGE VOLTAGE SETTINGS
ENABLED
UnderFREQ TRIP
58.0Hz
ALARMS
UndrFREQ ALARM
59.0Hz
AuxReLaY
A
RELAY A UF ALARM
ENABLED
Applied Freq.
TRIP
UF ALARM
FREQ OUT OF BOUNDS ALARM
RELAY A Operation
1 to 50.8
NO
NO
YES
YES
51.1 to 57.95
YES
YES
NO
YES
58.1 to 58.95
NO
YES
NO
YES
59.0 to 69.7
NO
NO
NO
NO
>70 NO
NO
YES
YES
EXAMPLE 2
ProGRam SETting
SYSTEM FREQ
50Hz
VOLTAGE VOLTAGE SETTINGS
ENABLED
UnderFREQ
49.8Hz
OverFREQ
50.2
Hz
ALARMS
UndrFREQ
49.8Hz
OverFREQ
50.2Hz
AuxReLaY
A
RELAY A UF ALARM
ENABLED
RELAY A OF ALARM
ENABLED
Applied Freq.
TRIP
UF ALARM
OF ALARM
FREQ OUT OF BOUNDS ALARM
RELAY A Operation
1 to 42.9
NO
NO
NO
YES
YES
43.1 to 49.5
YES
YES
NO
NO
YES
49.85 to 50.15
NO
NO
NO
NO
NO
50.3 to 58.7
YES
NO
YES
NO
YES
>59 NO
NO NO
YES
YES
