Siemens SG8158-00 manual Glossary

Glossary

Phase Sequence Voltage (47) Relay function that pro- tects against a phase sequence voltage condition. Tripping occurs when the phase sequence voltage indicated in the hardware configuration is not present at the device voltage inputs. This function operates without delay or inverse time characteristic.

Phase Time Overcurrent (51) A relay function that pro- tects against a phase overcurrent condition by using a selected time overcurrent characteristics curve to determine the trip time. Tripping occurs when any one phase current exceeds the programmed pickup at 100% or drops below the pickup at 95% for a period of time equal to the delay time setting. The pickup must remain active for the entire delay time for a trip to occur. If the overcurrent condition subsides in less time than the delay time, the pickup will go inactive and the phase time overcurrent function will reset. When trip- ping occurs, the actual condition that caused the trip is recorded in the device's nonvolatile trip log.

physical input Hardware connection to a device, such as a binary input.

physical output A trip contact or binary output of a device.

Pickup Begin of timing.

Pickup LED Light-emitting diode (red) indicating a protec- tive function in pickup.

Pickup Source Voltage Parameter of the ISGS Overvolt- age (59) protective function that indicates the VT connection. If the VTs are connected line-to-ground, the device can pickup up on line-to-line or line-to-ground voltages. If the VTs are connected line-to-line, the VTs can only pickup on line- to-line voltages.

Power Flow A parameter of the CT Configuration function that can be set to indicate whether power enters (normal) or leaves (reverse) the polarity mark on the CTs.

Power On display The first LCD display shown when the ISGS relay is powered on. Its first line indicates the relay con- figuration, the second line displays the relay's catalog num- ber.

Power On Meter display The LCD display that automati- cally replaces the Power On display after five seconds when the ISGS relay is powered on. Each line indicates a mea- sured value that can be changed in address block 7000 of an ISGS relay.

Qualified Person One who is familiar with the installation, construction, and operation of this equipment, and the haz- ards involved. In addition, this person has the following quali- fications: (1) training and authorization to energize, de- energize, clear, ground, and tag circuits and equipment in accordance with the established safety practices; (2) training in the proper care and use of protective equipment such as rubber gloves, hard hat, safety glasses or face shields, flash clothing, etc., in accordance with established safety proce- dures; (3) training in rendering first aid.

RMS filter Sensing method.

Setpoint In a feedback control loop, the point that deter- mines the desired value of the quantity to be controlled.

standard operating procedures Routine steps describ- ing how to display data, configure parameters, save changes, and switch parameter sets when manually operat- ing the ISGS relay.

system LED Light-emitting diode (green) indicating the proper operation of the relay.

Time Delay A parameter of several ISGS protective func- tions that sets the time between pickup and trip. If the func- tion remains in pickup for longer than the time delay, the function causes a trip.

Time Dial Parameter of several ISGS protective functions with characteristic curves that allows the raising or lowering of the time-to-trip.

Trip Coil Continuity Relay function that can be enabled to sense a trip coil continuity error and cause an action to be taken and an event being logged if the a- and b-switches are ever both continuously open for more than 100 ms. No other time delay is implemented. When this function detects the error, it is considered to be in pickup. It goes out of pickup when the condition is no longer present.

Trip LED Light-emitting diode (red) indicating that a protec- tive function or remote command has initiated a trip. Reset by depressing the Target Reset key.

trip log Contains information of a protective function trip event.

Trip Source Impedance Relay function that can be set to monitor the trip supply voltage (auxiliary voltage, station bat- tery) and perform an action if the voltage drops below ANSI minimums. This function can only be used in true DC trip systems.

tripping actuator Mechanism	that is held in	a charged
position with a permanent magnet while the circuit breaker is
open. When the mechanism is released, it causes the trip-
ping of a circuit breaker. The output signal from a trip unit
energizes a coil inside the actuator causing the magnetic flux
to shift to a new path. This shift releases the stored energy of
a spring located inside the actuator and trips the circuit
breaker. When the circuit breaker mechanism opens, the
actuator is automatically returned to the charged-and-held
position by a reset mechanism. A second coil inside the trip-
ping actuator is used to augment the holding power of the
permanent magnet during high short circuit conditions so
that stray magnetic fields will not cause unintended release
or demagnetization while the trip unit is in short time delay.
Underfrequency (81U) Relay	function that	protects
			G
against an underfrequency condition. Tripping occurs when

the frequency drops below the programmed underfrequency pickup for a period of time equal to the delay time setting. The pickup must remain active for the entire delay time for a

Siemens Energy & Automation, Inc. G-iii