GE Multilin D60 Line Distance Protection System 5-55 SETTINGS 5.1 OVERVIEW5Many settings are common to most elements and are discussed below:• FUNCTION setting: This setting programs the element to be operational when selected as “Enabled”. The factorydefault is “Disabled”. Once programmed to “Enabled”, any element associated with the function becomes active and alloptions become available.• NAME setting: This setting is used to uniquely identify the element.• SOURCE setting: This setting is used to select the parameter or set of parameters to be monitored.• PICKUP setting: For simple elements, this setting is used to program the level of the measured parameter above orbelow which the pickup state is established. In more complex elements, a set of settings may be provided to define therange of the measured parameters which will cause the element to pickup.• PICKUP DELAY setting: This setting sets a time-delay-on-pickup, or on-delay, for the duration between the pickupand operate output states.• RESET DELAY setting: This setting is used to set a time-delay-on-dropout, or off-delay, for the duration between theOperate output state and the return to logic 0 after the input transits outside the defined pickup range.• BLOCK setting: The default output operand state of all comparators is a logic 0 or “flag not set”. The comparatorremains in this default state until a logic 1 is asserted at the RUN input, allowing the test to be performed. If the RUNinput changes to logic 0 at any time, the comparator returns to the default state. The RUN input is used to supervisethe comparator. The BLOCK input is used as one of the inputs to RUN control.• TARGET setting: This setting is used to define the operation of an element target message. When set to “Disabled”,no target message or illumination of a faceplate LED indicator is issued upon operation of the element. When set to“Self-Reset”, the target message and LED indication follow the operate state of the element, and self-resets once theoperate element condition clears. When set to “Latched”, the target message and LED indication will remain visibleafter the element output returns to logic 0 until a RESET command is received by the relay.• EVENTS setting: This setting is used to control whether the pickup, dropout or operate states are recorded by theevent recorder. When set to “Disabled”, element pickup, dropout or operate are not recorded as events. When set to“Enabled”, events are created for:(Element) PKP (pickup)(Element) DPO (dropout)(Element) OP (operate)The DPO event is created when the measure and decide comparator output transits from the pickup state (logic 1) tothe dropout state (logic 0). This could happen when the element is in the operate state if the reset delay time is not 0.5.1.3 INTRODUCTION TO AC SOURCESa) BACKGROUNDThe D60 may be used on systems with breaker-and-a-half or ring bus configurations. In these applications, each of the twothree-phase sets of individual phase currents (one associated with each breaker) can be used as an input to a breaker fail-ure element. The sum of both breaker phase currents and 3I_0 residual currents may be required for the circuit relayingand metering functions. For a three-winding transformer application, it may be required to calculate watts and vars for eachof three windings, using voltage from different sets of VTs. These requirements can be satisfied with a single UR, equippedwith sufficient CT and VT input channels, by selecting the parameter to measure. A mechanism is provided to specify theAC parameter (or group of parameters) used as the input to protection/control comparators and some metering elements.Selection of the parameter(s) to measure is partially performed by the design of a measuring element or protection/controlcomparator by identifying the type of parameter (fundamental frequency phasor, harmonic phasor, symmetrical component,total waveform RMS magnitude, phase-phase or phase-ground voltage, etc.) to measure. The user completes the processby selecting the instrument transformer input channels to use and some of the parameters calculated from these channels.The input parameters available include the summation of currents from multiple input channels. For the summed currents ofphase, 3I_0, and ground current, current from CTs with different ratios are adjusted to a single ratio before summation.A mechanism called a source configures the routing of CT and VT input channels to measurement sub-systems. Sources,in the context of UR series relays, refer to the logical grouping of current and voltage signals such that one source containsall the signals required to measure the load or fault in a particular power apparatus. A given source may contain all or someof the following signals: three-phase currents, single-phase ground current, three-phase voltages and an auxiliary voltagefrom a single VT for checking for synchronism.