Document ID: PRELIMINARY VERSION

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1 Directional residual overcurrent protection function block description Document ID: PRELIMINARY VERSION

2 User s manual version information Version Date Modification Compiled by Preliminary Preliminary version, without technical information Petri Technical information added Petri New Fig. 1-2 added Petri PRELIMINARY VERSION 2/12

3 CONTENTS 1 function Application Mode of operation Structure of the directional residual overcurrent protection algorithm Enabling the directional decision (Comparison ) Calculation of the vector angle (FI calculation) Directional decision (DIRST) Non-directional residual overcurrent protection function (TOC51N) Technical summary Technical data Summary of the parameters Summary of the generated output signals Summary of the input signals The function block PRELIMINARY VERSION 3/12

4 1 function 1.1 Application The main application area of the directional residual overcurrent protection function is l earthfault protection. 1.2 Mode of operation The inputs of the function are the Fourier basic harmonic components of the zero sequence current and those of the zero sequence voltage. The block of the directional decision generates a signal of TRUE value if the UN=3Uo zero sequence voltage and the IN=-3Io current is sufficient for directional decision, and the angle difference between the vectors is within the preset range. This decision enables the output start and trip signal of an overcurrent protection function block (TOC51N). Note: the position of the vectors in Figure 1-1 indicates a forward fault, i.e., the location of the earth fault is on the protected line (the positive direction of the current is from the busbar to the line). jx +R0A Z -R0A Fi RCA R Figure 1-1 The directional decision (setting on the impedance plane) jim 3Io (180-FI) U Uphase Re Un=3Uo Figure 1-2 The directional decision (injected vectors on the complex plane) PRELIMINARY VERSION 4/12

5 1.3 Structure of the directional residual overcurrent protection algorithm Fig.1-2 shows the structure of the directional residual overcurrent protection (TOC51N) algorithm. UNFour TOC 67N AND INFour FI OK φ DIRST OR DIR_OK TOC 51N Signals Parameters Signals Direction=NonDir Figure 1-3 Structure of the residual directional overcurrent protection algorithm The inputs are the RMS value of the fundamental Fourier component of the residual current (IN=3Io), the RMS value of the fundamental Fourier component of the residual voltage (UN=3Uo), parameters, status signals. The outputs are the binary output status signals. The software modules of the residual directional overcurrent protection function: Comparison These modules decide if the RMS values of the fundamental Fourier component of the residual current and voltage are above the limits needed for correct directional decision. FI calculation This module calculates the vector angle between the residual voltage and the residual current. DIRST The directional decision. TOC51N Non-directional residual overcurrent protection function. The following description explains the details of the individual components. PRELIMINARY VERSION 5/12

6 1.3.1 Enabling the directional decision (Comparison ) These modules decide if the RMS values of the fundamental Fourier component of the residual current and voltage are above the limits needed for correct directional decision. Integer parameters Parameter name Title Unit Min Max Step Default The threshold value for the 3Uo zero sequence voltage, below which no directionality is possible. % of the rated voltage of the voltage transformer input. TOC67N_UoMin_IPar_ Uo min % The threshold value for the 3Io zero sequence current, below which no operation is possible. % of the rated current of the current transformer input. TOC67N_IoMin_IPar_ Io min % Table 1-1 The integer parameters for enabling the directional decision The input signals are the RMS values of the fundamental Fourier component of the residual current and voltage. The internal output status signal for enabling the directional decision is true if both the residual voltage and the residual current is above the preset limits Calculation of the vector angle (FI calculation) This module calculates the phase angle between the residual voltage and the residual current. The reference signal is the residual voltage according to Figure 1-1. The input signals are the fundamental Fourier components of the residual current and voltage. The internal output signal is the calculated phase angle Directional decision (DIRST) This module decides if the phase angle between the residual voltage and the residual current is within the limit range defined by the preset parameter. The operation of this function is explained in Figure 1-1. The input signals are The enabling status signal from the Comparison modules in AND relationship. The calculated phase angle between the residual voltage and the residual current. Parameters. The internal output signal is the decision if the direction is OK, which is TRUE if the phase angle between the residual voltage and the residual current is within the limit range defined by the preset parameter OR if non-directional operation is selected by the preset parameter TOC67N_Dir_EPar_ (Direction=NonDir). PRELIMINARY VERSION 6/12

7 Enumerated parameters Parameter name Title Selection range Default Directionality of the function TOC67N_Dir_EPar_ Direction NonDir,Forward,Backward* Forward *The forward direction is defined by the RCA characteristic angle (See Tables 1-4 below). Tables 1-2 The enumerated parameters of the directional decision Integer parameters Parameter name Title Unit Min Max Step Default Operating angle (See Figure 1-1) TOC67N_ROA_IPar_ Operating Angle deg Characteristic angle (See Figure 1-1) TOC67N_RCA_IPar_ Characteristic Angle deg Table 1-3 Integer parameters of the directional decision Non-directional residual overcurrent protection function (TOC51N) This module is equivalent to the TOC51N function block described in a separate document. Summary of the parameters: Enumerated parameters Parameter name Title Selection range Default Operating characteristic selection of the TOC51N module Off,DefiniteTime,IEC Inv,IEC VeryInv,IEC ExtInv,IEC LongInv,ANSI TOC67N_Oper_EPar_ Operation Inv,ANSI ModInv,ANSI VeryInv,ANSI ExtInv,ANSI LongInv,ANSI LongVeryInv,ANSI LongExtInv DefiniteTime Tables 1-4 The enumerated parameters of the TOC51N function block Integer parameters Parameter name Title Unit Min Max Step Default Start current of the inverse characteristics (TOC51N module) TOC67N_StCurr_IPar_ Start current % Table 1-5 Integer parameters of the TOC51N function block Float parameters Parameter name Title Unit Min Max Digits Default Time multiplier of the inverse characteristics (TOC51N module) TOC67N_Multip_FPar_ Time Mult sec Table 1-6 Float parameters of the TOC51N function block PRELIMINARY VERSION 7/12

8 Timer parameters Parameter name Title Unit Min Max Step Default Minimal time delay for the inverse characteristics (TOC 51N module): TOC67N_MinDel_TPar Min. Time msec _ Definite time delay for the inverse characteristics (TOC 51N module): TOC67N_DefDel_TPar Definite Time msec _ Reset time delay for the inverse characteristics (TOC 51N module): TOC67N_Reset_TPar_ Reset Time msec Table 1-7 Timer parameters of the TOC51N function block The output status signals of the TOC51N function block are identical with those of the TOC67N function: Binary status signal Title Explanation TOC67N_GenSt_GrI_ Start General start signal of the function TOC67N_GenTr_GrI_ Trip General trip command of the function Table 1-8 The binary output status signals of the TOC51N function block PRELIMINARY VERSION 8/12

9 1.4 Technical summary Technical data Function Effective range* Accuracy* Definite time characteristics Operating characteristic accuracy Definite time <2% Reset ratio 0.95 Operate time accuracy At Time delay 100 ms <30 ms At Time delay>100 ms <3 ms Reset time ms Inverse time characteristics Operating characteristic accuracy Inverse time, according to parameter selection <2% Reset ratio 0.95 Operate time accuracy <30 ms ms Reset time Or according to reset characteristics Directional characteristics Angular accuracy <3 Table 1-9 Technical data of the directional residual overcurrent protection function PRELIMINARY VERSION 9/12

10 1.4.2 Summary of the parameters Enumerated parameters Parameter name Title Selection range Default Directionality of the function TOC67N_Dir_EPar_ Direction NonDir,Forward,Backward Forward Operating characteristic selection of the TOC51N module Off,DefiniteTime,IEC Inv,IEC VeryInv,IEC ExtInv,IEC LongInv,ANSI Inv,ANSI TOC67N_Oper_EPar_ Operation ModInv,ANSI VeryInv,ANSI ExtInv,ANSI LongInv,ANSI LongVeryInv,ANSI LongExtInv DefiniteTime Table 1-10 The enumerated parameters of the directional residual overcurrent protection function Integer parameters Parameter name Title Unit Min Max Step Default The threshold value for the 3Uo zero sequence voltage, below which no directionality is possible. % of the rated voltage of the voltage transformer input. TOC67N_UoMin_IPar_ Uo min % The threshold value for the 3Io zero sequence current, below which no operation is possible. % of the rated current of the current transformer input. TOC67N_IoMin_IPar_ Io min % Operating angle (See Figure 1-1) TOC67N_ROA_IPar_ Operating Angle deg Characteristic angle (See Figure 1-1) TOC67N_RCA_IPar_ Characteristic Angle deg Start current of the inverse characteristics (TOC51N module) TOC67N_StCurr_IPar_ Start current % Table 1-11 Integer parameters of the directional residual overcurrent protection function PRELIMINARY VERSION 10/12

11 Float parameters Parameter name Title Unit Min Max Digits Default Time multiplier of the inverse characteristics (TOC51N module) TOC67N_Multip_FPar_ Time Mult sec Table 1-12 Float parameters of the directional residual overcurrent protection function Timer parameters Parameter name Title Unit Min Max Step Default Minimal time delay for the inverse characteristics (TOC 51N module): TOC67N_MinDel_TPar_ Min. Time msec Definite time delay for the inverse characteristics (TOC 51N module): TOC67N_DefDel_TPar_ Definite Time msec Reset time delay for the inverse characteristics (TOC 51N module): TOC67N_Reset_TPar_ Reset Time msec Table 1-13 Timer parameters of the directional residual overcurrent protection function Summary of the generated output signals Binary status signal Title Explanation TOC67N_GenSt_GrI_ Start General start signal of the function TOC67N_GenTr_GrI_ Trip General trip command of the function Table 1-14 The binary output status signals of the directional residual overcurrent protection function Summary of the input signals Binary status signals The directional residual overcurrent protection function has a binary input status signal. The conditions are defined by the user applying the graphic equation editor. Binary status signal Title Explanation TOC67N_Blk_GrO_ Block Blocking input status signal Table 1-15 The binary input signal of the directional residual overcurrent protection function PRELIMINARY VERSION 11/12

12 1.4.5 The function block The function block of the residual directional overcurrent protection function is shown in Figure 1-4. This block shows all binary input and output status signals that are applicable in the graphic equation editor. Figure 1-4 The function block of the residual overcurrent protection function The names of the input and output signals are parts of the Binary status signal names listed in Table 1-14 and Table 1-15 above. PRELIMINARY VERSION 12/12

Directional three-phase overcurrent protection function block description

Directional three-phase overcurrent protection function block description Document ID: PRELIMINARY VERSION Budapest, October 2009 User s manual version information Version Date Modification Compiled by