GE F60 Instruction Manual

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GE F60 Instruction Manual Manual pdf 92 page image

5-4 F60 Feeder Management Relay GE Multilin5.1 OVERVIEW 5 SETTINGS55.1.2 INTRODUCTION TO ELEMENTSIn the design of UR relays, the term “element” is used to describe a feature that is based around a comparator. The com-parator is provided with an input (or set of inputs) that is tested against a programmed setting (or group of settings) to deter-mine if the input is within the defined range that will set the output to logic 1, also referred to as “setting the flag”. A singlecomparator may make multiple tests and provide multiple outputs; for example, the time overcurrent comparator sets aPickup flag when the current input is above the setting and sets an Operate flag when the input current has been at a levelabove the pickup setting for the time specified by the time-current curve settings. All comparators, except the Digital Ele-ment which uses a logic state as the input, use analog parameter actual values as the input.Elements are arranged into two classes, GROUPED and CONTROL. Each element classed as a GROUPED element isprovided with six alternate sets of settings, in setting groups numbered 1 through 6. The performance of a GROUPED ele-ment is defined by the setting group that is active at a given time. The performance of a CONTROL element is independentof the selected active setting group.The main characteristics of an element are shown on the element logic diagram. This includes the input(s), settings, fixedlogic, and the output operands generated (abbreviations used on scheme logic diagrams are defined in Appendix F).Some settings for current and voltage elements are specified in per-unit (pu) calculated quantities:pu quantity = (actual quantity) / (base quantity)• For current elements, the ‘base quantity’ is the nominal secondary or primary current of the CT. Where the currentsource is the sum of two CTs with different ratios, the ‘base quantity’ will be the common secondary or primary currentto which the sum is scaled (i.e. normalized to the larger of the 2 rated CT inputs). For example, if CT1 = 300 / 5 A andCT2 = 100 / 5 A, then in order to sum these, CT2 is scaled to the CT1 ratio. In this case, the ‘base quantity’ will be 5 Asecondary or 300 A primary.• For voltage elements the ‘base quantity’ is the nominal primary voltage of the protected system which corresponds(based on VT ratio and connection) to secondary VT voltage applied to the relay. For example, on a system with a13.8 kV nominal primary voltage and with 14400:120 V Delta-connected VTs, the secondary nominal voltage (1 pu)would be:(EQ 5.1)For Wye-connected VTs, the secondary nominal voltage (1 pu) would be:(EQ 5.2)Many 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 andall options 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.1380014400---------------- 120× 115 V=1380014400---------------- 1203----------× 66.4 V=