GE Multilin N60 Network Stability and Synchrophasor Measurement System 5-995 SETTINGS 5.5 FLEXLOGIC™5The logic that determines the interaction of inputs, elements, schemes and outputs is field programmable through the useof logic equations that are sequentially processed. The use of virtual inputs and outputs in addition to hardware is availableinternally and on the communication ports for other relays to use (distributed FlexLogic™).FlexLogic™ allows users to customize the relay through a series of equations that consist of operators and operands. Theoperands are the states of inputs, elements, schemes and outputs. The operators are logic gates, timers and latches (withset and reset inputs). A system of sequential operations allows any combination of specified operands to be assigned asinputs to specified operators to create an output. The final output of an equation is a numbered register called a virtual out-put. Virtual outputs can be used as an input operand in any equation, including the equation that generates the output, as aseal-in or other type of feedback.A FlexLogic™ equation consists of parameters that are either operands or operators. Operands have a logic state of 1 or 0.Operators provide a defined function, such as an AND gate or a Timer. Each equation defines the combinations of parame-ters to be used to set a Virtual Output flag. Evaluation of an equation results in either a 1 (=ON, i.e. flag set) or 0 (=OFF, i.e.flag not set). Each equation is evaluated at least 4 times every power system cycle.Some types of operands are present in the relay in multiple instances; e.g. contact and remote inputs. These types of oper-ands are grouped together (for presentation purposes only) on the faceplate display. The characteristics of the differenttypes of operands are listed in the table below.Table 5–7: N60 FLEXLOGIC™ OPERAND TYPESOPERAND TYPE STATE EXAMPLE FORMAT CHARACTERISTICS[INPUT IS ‘1’ (= ON) IF...]Contact Input On Cont Ip On Voltage is presently applied to the input (external contactclosed)Off Cont Ip Off Voltage is presently not applied to the input (externalcontact open)Contact Output(type Form-A contactonly)Current On Cont Op 1 Ion Current is flowing through the contactVoltage On Cont Op 1 VOn Voltage exists across the contactVoltage Off Cont Op 1 VOff Voltage does not exists across the contactDirect Input On DIRECT INPUT 1 On The direct input is presently in the ON stateElement(Analog)Pickup PHASE TOC1 PKP The tested parameter is presently above the pickup settingof an element which responds to rising values or below thepickup setting of an element which responds to fallingvaluesDropout PHASE TOC1 DPO This operand is the logical inverse of the above PKPoperandOperate PHASE TOC1 OP The tested parameter has been above/below the pickupsetting of the element for the programmed delay time, orhas been at logic 1 and is now at logic 0 but the reset timerhas not finished timingBlock PHASE TOC1 BLK The output of the comparator is set to the block functionElement(Digital)Pickup Dig Element 1 PKP The input operand is at logic 1Dropout Dig Element 1 DPO This operand is the logical inverse of the above PKPoperandOperate Dig Element 1 OP The input operand has been at logic 1 for the programmedpickup delay time, or has been at logic 1 for this period andis now at logic 0 but the reset timer has not finished timingElement(Digital Counter) Higher than Counter 1 HI The number of pulses counted is above the set numberEqual to Counter 1 EQL The number of pulses counted is equal to the set numberLower than Counter 1 LO The number of pulses counted is below the set numberFixed On On Logic 1Off Off Logic 0Remote Input On REMOTE INPUT 1 On The remote input is presently in the ON stateVirtual Input On Virt Ip 1 On The virtual input is presently in the ON stateVirtual Output On Virt Op 1 On The virtual output is presently in the set state (i.e.evaluation of the equation which produces this virtualoutput results in a "1")
