1MRS752345-MUM Issued: 10/1997 Version: F/21.08.2003 Data subject to change without notice Three-Phase Voltage Measurement Contents 1. Introduction...2 1.1 Features...2 1.2 Application...2 1.3 Input description...3 1.4 Output description...3 2. Description of operation... 4 2.1 Configuration...4 2.2 Measuring mode...4 2.3 Registers...4 2.4 Actual voltage measurement...5 2.5 Maximum and minimum s...5 2.6 Zero value supervision and zero value detection...5 2.7 Threshold supervision with absolute threshold...6 2.8 Threshold supervision with integrator algorithm...7 2.9 Threshold supervision with time-based function...8 2.10 Limit value supervision...8 3. Parameters and events... 10 3.1 General...10 3.2 Control settings...11 3.3 Measurement values...12 3.3.1 Input data...12 3.3.2 Recorded data...13 3.3.3 Events...14 4. Technical data... 17
Substation Automation 1. Introduction 1.1 Features True RMS measurement of phase or phase-to-phase voltages Actual voltage values displayed in voltages and as p.u. values Average voltage supervision with adjustable time intervals Threshold supervision for voltages by the integration, absolute or time-based method Limit value monitoring for each voltage with up to four adjustable limits Voltages to be measured by means of conventional voltage transformers or voltage dividers Voltage outputs to be used in the freely programmable logic of the Relay Configuration Tool included in the CAP 505 Tool Box Virtual phase-to-phase voltage measurement channels can be used instead of the corresponding analogue measurement channels 1.2 Application This document specifies the functions of the three-phase voltage measurement function blocks MEVO3A and MEVO3B that are identical in operation. The three-phase voltage measurement function blocks can be used in various applications and products based on the RED 500 Platform, e.g. feeder terminals, infeeder terminals, motor protection terminals and transformer protection terminals. Figure 1. Function block symbols MEVO3A and MEVO3B 2
Substation Automation 1.3 Input description Name Type Description UL1_U12 Analogue signal (SINT) Input for measuring voltage U L1 / U 12 UL2_U23 Analogue signal (SINT) Input for measuring voltage U L2 / U 23 UL3_U31 Analogue signal (SINT) Input for measuring voltage U L3 / U 31 RESET Reset signal (BOOL, pos. edge) Input signal for resetting the registers of the function block 1.4 Output description Name Type Description UL1_U12MEAS Analogue signal (REAL) Measured value of voltage U L1 / U 12 (kv) UL2_U23MEAS Analogue signal (REAL) Measured value of voltage U L2 / U 23 (kv) UL3_U31MEAS Analogue signal (REAL) Measured value of voltage U L3 / U 31 (kv) HighWarning HighAlarm LowWarning LowAlarm ERR Digital signal (BOOL, active high) Digital signal (BOOL, active high) Digital signal (BOOL, active high) Digital signal (BOOL, active high) Digital signal (BOOL, active high) Indication of an exceeded high warning limit Indication of an exceeded high alarm limit Indication of an exceeded low warning limit Indication of an exceeded low alarm limit Indication of a configuration error 3
Substation Automation 2. Description of Operation 2.1 Configuration The analogue channel numbers for the corresponding UL1_U12, UL2_U23 and UL3_U31 inputs are selected by means of the Relay Configuration Tool. Conventional voltage transformers or voltage dividers can be used for measuring the voltages. The function block automatically adapts its operation to the channels and measuring devices selected in the configuration tool. The following voltages can be connected to each Uchx input: Input name Measured voltage UL1_U12 U L1, U L1b, U L1c, U 12, U 12b, U 12s or U 12bs, UL2_U23 UL3_U31 U L2, U L2b, U 23, U 23b, U 23s or U 23bs U L3, U L3b, U 31, U 31b, U 31s or U 31bs Both phase-to-phase and phase-to-earth voltages can be connected to the function block at the same time. Two voltage inputs can also be left without a connection. When all three voltage inputs are unconnected, the output signal ERR is set to TRUE. 2.2 Measuring mode The function block measures true RMS phase-to-earth or phase-to-phase voltages. If voltage dividers are used, only phase-to-earth voltages can be measured. Note that RMS measurement must be selected for the voltage inputs via the Special Measurements dialogue of the configuration tool. The voltage values are updated once per fundamental frequency cycle, i.e. the integration time for true RMS calculation is one fundamental cycle. 2.3 Registers The following values are recorded: maximum for each channel with date and time stamps minimum for each channel with date and time stamps The registers can be reset via the RESET input, or over the serial bus or the local MMI. 4
Substation Automation 2.4 Actual voltage measurement Actual voltage values are displayed in voltages and as p.u. values. The parameter Phase selection is used for selecting the voltages to be measured. If a voltage has not been selected, the actual voltage value will be zero and the supervision functions are not executed on that particular voltage. 2.5 Maximum and minimum s Maximum and minimum average functions are implemented by means of a function that calculates the linear average of the voltages measured over a settable average time interval (parameter Average interval ). A new average value is obtained once a minute, indicating the actual over the average time interval preceding the update time. The actual rolling average values are stored in the memory until the value is updated at the end of the following time interval. Actual s are measured separately in each channel. If the new value exceeds the maximum average value recorded, the actual average value will replace the maximum average value recorded. Should the new actual average be smaller than the minimum average recorded, the actual average value will replace the recorded minimum average. Maximum and minimum values are provided with date and time stamps. Maximum and minimum values are cleared when the registers are reset. 2.6 Zero value supervision and zero value detection A voltage below 1.0% U n is forced to 0% U n. This allows the noise in the input voltage to be ignored. The zero value supervision is fixed to 1.0% U n and is always active. The zero value detection function is used to force a voltage value update if it deviates slightly from zero or is zero. Zero value detection operates so that once a voltage passes (upwards or downwards) the limit 1.0% U n, the new voltage value is spontaneously reported to the master device (MicroSCADA), provided the threshold supervision with an absolute threshold or the integration method is in use (see the control parameter Threshold select ). 5
Substation Automation 2.7 Threshold supervision with absolute threshold Three different methods can be used for threshold supervision (also known as delta supervision) and the method to be used is selected with the parameter Threshold select. Parameter Phase selection can be used to select which phases are supervised. In absolute threshold supervision, the function block compares the actual voltage value with the last reported value. If the actual value exceeds the last reported value plus the set Threshold value or is below the last reported value minus the set Threshold value, the actual value is spontaneously reported to the master device and will replace the last reported value. Voltage Voltage value update Voltage value update Reported value + Threshold value - Threshold value Reported value Minimum threshold 0 Execution task cycle Figure 2. Operation of threshold supervision with absolute algorithm Note that the setting Time interval has no effect on the absolute method. 6
Substation Automation 2.8 Threshold supervision with integrator algorithm In threshold supervision with integrator algorithm, the function block calculates the difference between the last reported voltage value and the actual value for each task cycle. The difference is added to the internal accumulated (integrated) value register. If the accumulated delta exceeds the set Threshold value multiplied by time interval, the actual value is spontaneously reported to the master device and will replace the last reported value. Also the internal threshold difference register is reset and the supervision starts over. The settings Threshold value and Time interval can be interpreted as follows: threshold defines the accuracy of the measured quantity and time interval defines the response time, i.e. the longest time period the changed value can wait before being transmitted. Figure 3. Operation of threshold supervision with integrator algorithm Example 1: Measurement value has changed 1% after the last sent measurement value. Threshold value = 1% and Time interval = 1s -> new measurement value is sent after 1 second. Example 2: 7
Substation Automation Measurement value has changed 1% after the last sent measurement value. Threshold value = 1% and Time interval = 2s -> new measurement value is sent after 2 seconds. Example 3: Measurement value has changed 2% after the last sent measurement value. Threshold value = 10% and Time interval = 2s -> new measurement value is sent after 10 seconds. 2.9 Threshold supervision with time-based function If the time-based threshold supervision is used, the function block sends the values to the master device at intervals selected with the control parameter Time interval. Note that threshold setting has no effect on the time-based method. 2.10 Limit value supervision For all three phase voltages, up to four different limits can be monitored. The parameter Limit selection is used to specify the limit to be supervised and monitored. Each phase and limit is checked independently, which means that if a phase voltage exceeds several limits during an execution task cycle, each exceeding of limit is reported to the master device independently. The hysteresis of each limit is fixed to 1% of the nominal value and taken into account as shown below. Each exceeding of limit with a time stamp is stored with the FIFO method. The outputs HighWarning, HighAlarm, LowWarning and LowAlarm are activated as shown below. The warning and alarm limits can be changed on-line. 8
Substation Automation Figure 4. Operation of limit value monitoring 9
Substation Automation 3. Parameters and Events 3.1 General Each function block has a specific channel number for serial communication parameters and events. The channel for MEVO3A is 204 and that for MEVO3B 206. The data direction of the parameters defines the use of each parameter as follows: Data direction Description R, R/M Read only W R/W Write only Read and write The different event mask parameters (see section Control settings ) affect the visibility of events on the MMI or on serial communication (LON or SPA) as follows: Event mask 1 (FxxxV101/102) Event mask 2 (FxxxV103/104) Event mask 3 (FxxxV105/106) Event mask 4 (FxxxV107/108) SPA / MMI (LON) LON LON LON For example, if only the events E3, E4 and E5 are to be seen on the MMI of the relay terminal, the event mask value 56 (8 + 16 + 32) is written to the Event mask 1 parameter (FxxxV101). In case a function block includes more than 32 events, there are two parameters instead of e.g. the Event mask 1 parameter: the parameter Event mask 1A (FxxxV101) covers the events 0...31 and Event mask 1B (FxxxV102) the events 32...63. 10
Substation Automation 3.2 Control settings Parameter Code Values Unit Default Data directio n Explanation Phase selection V1 0...6 1) - 0 R/W Selection of channels to be measured Average interval V2 0...5 2) - 1 R/W Time interval for average value Threshold select V3 0...3 3) - 0 R/W Selection of threshold supervision algorithm Threshold value V4 0.01...1.00 x Un 0.01 R/W Threshold value for threshold supervision Limit selection V5 0...9 4) - 0 R/W Selection of monitored limits High warning V6 0.80...1.50 x Un 1.00 R/W High warning limit value High alarm V7 0.80...1.50 x Un 1.10 R/W High alarm limit value Low warning V8 0.00...0.99 x Un 0.00 R/W Low warning limit value Low alarm V9 0.00...0.99 x Un 0.00 R/W Low alarm limit value Time interval V10 1 600 s 1 R/W Time interval for threshold supervision Event mask 1A V101 0...721420287-0 R/W Event mask 1 for event transmission (E0...E29) Event mask 1B V102 0...721420287-0 R/W Event mask 1 for event transmission (E32...E61) Event mask 2A V103 0...721420287-0 R/W Event mask 2 for event transmission (E0...E29) Event mask 2B V104 0...721420287-0 R/W Event mask 2 for event transmission (E32...E61) Event mask 3A V105 0...721420287-0 R/W Event mask 3 for event transmission (E0...E29) Event mask 3B V106 0...721420287-0 R/W Event mask 3 for event transmission (E32...E61) Event mask 4A V107 0...721420287-0 R/W Event mask 4 for event transmission (E0...E29) Event mask 4B V108 0...721420287-0 R/W Event mask 4 for event transmission (E32...E61) 1) Phase selection 0 = Uch1&Uch2&Uch3; 1 = Uch1 & Uch2; 2 = Uch2 & Uch3; 3 = Uch1 & Uch3; 4 = Uch1; 5 = Uch2; 6 = Uch3 2) Average interval 0 = 1 min; 1 = 5 min; 2 = 10 min; 3 = 15 min; 4 = 30 min; 5 = 60 min 3) Threshold select 0 = Not in use; 1 = Absolute alg.; 2 = Integrat. alg.; 3 = Time interval 4) Limit selection 0 = Not in use; 1 = HW, HA, LW, LA; 2 = HW, HA; 3 = LW, LA; 4 = HW, LW; 5 = HA, LA; 6 = HW; 7 = HA; 8 = LW; 9 = LA 11
Substation Automation 3.3 Measurement values 3.3.1 Input data Parameter Code Values Unit Default Data direction Explanation UL1_U12 I1 0.00...999.99 kv 0.00 R/M Voltage U L1 _U 12 in voltages UL2_U23 I2 0.00...999.99 kv 0.00 R/M Voltage U L2 _U 23 in voltages UL3_U31 I3 0.00...999.99 kv 0.00 R/M Voltage U L3 _U 31 in voltages UL1_U12 I4 0.00...2.00 x Un 0.00 R/M Voltage U L1 _U 12 in percent UL2_U23 I5 0.00...2.00 x Un 0.00 R/M Voltage U L2 _U 23 in percent UL3_U31 I6 0.00...2.00 x Un 0.00 R/M Voltage U L3 _U 31 in percent UL1_U12 average I7 0.00...999.99 kv 0.00 R/M Average value of U L1 _U 12 in voltages UL2_U23 average I8 0.00...999.99 kv 0.00 R/M Average value of U L2 _U 23 in voltages UL3_U31 average I9 0.00...999.99 kv 0.00 R/M Average value of U L3 _U 31 in voltages UL1_U12 average I10 0.00...2.00 x Un 0.00 R/M Average value of U L1 _U 12 in percent UL2_U23 average I11 0.00...2.00 x Un 0.00 R/M Average value of U L2 _U 23 in percent UL3_U31 average I12 0.00...2.00 x Un 0.00 R/M Average value of U L3 _U 31 in percent Input RESET I13 0 or 1 1) - 0 R/M Signal for resetting the demand values and registers of the function block 1) Input RESET 0 = Not active; 1 = Active 12
Substation Automation 3.3.2 Recorded data Parameter Code Values Unit Default Data direction Explanation U1_12 max date V201 YYYY-MM-DD - - R/M Date of U L1 _U 12 maximum U1_12 max time V202 hh:mm:ss.000 - - R/M Time of U L1 _U 12 maximum U1_12 max (kv) V203 0.00...999.99 kv 0.00 R/M Maximum average of U L1 _U 12 in voltages U1_12 max (pu) V204 0.00...2.00 x Un 0.00 R/M Maximum average of U L1 _U 12 in percent U2_23 max date V205 YYYY-MM-DD - - R/M Date of U L2 _U 23 maximum U2_23 max time V206 hh:mm:ss.000 - - R/M Time of U L2 _U 23 maximum U2_23 max (kv) V207 0.00...999.99 kv 0.00 R/M Maximum average of U L2 _U 23 in voltages U3_23 max (pu) V208 0.00...2.00 x Un 0.00 R/M Maximum average of U L2 _U 23 in percent U3_31 max date V209 YYYY-MM-DD - - R/M Date of U L3 _U 31 maximum U3_31 max time V210 hh:mm:ss.000 - - R/M Time of U L3 _U 31 maximum U3_31 max (kv) V211 0.00...999.99 kv 0.00 R/M Maximum average of U L3 _U 31 in voltages U3_31 max (pu) V212 0.00...2.00 x Un 0.00 R/M Maximum average of U L3 _U 31 in percent U1_12 min date V213 YYYY-MM-DD - - R/M Date of U L1 _U 12 minimum U1_12 min time V214 hh:mm:ss.000 - - R/M Time of U L1 _U 12 minimum U1_12 min (kv) V215 0.00...999.99 kv 999.99 R/M Minimum average of U L1 _U 12 in voltages U1_12 min (pu) V216 0.00...2.00 x Un 2.00 R/M Minimum average of U L1 _U 12 in percent U2_23 min date V217 YYYY-MM-DD - - R/M Date of U L2 _U 23 minimum U2_23 min time V218 hh:mm:ss.000 - - R/M Time of U L2 _U 23 minimum U2_23 min (kv) V219 0.00...999.99 kv 999.99 R/M Minimum average of U L2 _U 23 in voltages Table continues on the next page. 13
Substation Automation Parameter Code Values Unit Default Data direction Explanation U2_23 min (pu) V220 0.00...2.00 x Un 2.00 R/M Minimum average of U L2 _U 23 in percent U3_31 min date V221 YYYY-MM-DD - - R/M Date of U L3 _U 31 minimum U3_31 min time V222 hh:mm:ss.000 - - R/M Time of U L3 _U 31 minimum U3_31 min (kv) V223 0.00...999.99 kv 999.99 R/M Minimum average of U L3 _U 31 in voltages U3_31 min (pu) V224 0.00...2.00 x Un 2.00 R/M Minimum average of U L3 _U 31 in percent 3.3.3 Events Events 0...31: Code Weighting coefficient Default mask Event reason Event state E0 1 0 UL1 High warning reset E1 2 0 UL1 High warning activated E2 4 0 UL2 High warning reset E3 8 0 UL2 High warning activated E4 16 0 UL3 High warning reset E5 32 0 UL3 High warning activated E6 64 0 UL1 High alarm reset E7 128 0 UL1 High alarm activated E8 256 0 UL2 High alarm reset E9 512 0 UL2 High alarm activated E10 1024 0 UL3 High alarm reset E11 2048 0 UL3 High alarm activated E12 4096 0 UL1 Low warning reset E13 8192 0 UL1 Low warning activated E14 16384 0 UL2 Low warning reset E15 32768 0 UL2 Low warning activated E16 65536 0 UL3 Low warning reset E17 131072 0 UL3 Low warning activated E18 262144 0 UL1 Low alarm reset E19 524288 0 UL1 Low alarm activated Table continues on the next page. 14
Substation Automation Code Weighting coefficient Default mask Event reason Event state E20 1048576 0 UL2 Low alarm reset E21 2097152 0 UL2 Low alarm activated E22 4194304 0 UL3 Low alarm reset E23 8388608 0 UL3 Low alarm activated E25 33554432 0 UL1 Delta E27 134217728 0 UL2 Delta E29 536870912 0 UL3 Delta 15
Substation Automation Events 32...61: Code Weighting coefficient Default mask Event reason Event state E32 1 0 U12 High warning reset E33 2 0 U12 High warning activated E34 4 0 U23 High warning reset E35 8 0 U23 High warning activated E36 16 0 U31 High warning reset E37 32 0 U31 High warning activated E38 64 0 U12 High alarm reset E39 128 0 U12 High alarm activated E40 256 0 U23 High alarm reset E41 512 0 U23 High alarm activated E42 1024 0 U31 High alarm reset E43 2048 0 U31 High alarm activated E44 4096 0 U12 Low warning reset E45 8192 0 U12 Low warning activated E46 16384 0 U23 Low warning reset E47 32768 0 U23 Low warning activated E48 65536 0 U31 Low warning reset E49 131072 0 U31 Low warning activated E50 262144 0 U12 Low alarm reset E51 524288 0 U12 Low alarm activated E52 1048576 0 U23 Low alarm reset E53 2097152 0 U23 Low alarm activated E54 4194304 0 U31 Low alarm reset E55 8388608 0 U31 Low alarm activated E57 33554432 0 U12 Delta E59 134217728 0 U23 Delta E61 536870912 0 U31 Delta 16
Substation Automation 4. Technical Data Operation accuracies Depends on the frequency of the voltage measured: f/f n = 0.95...1.05: ±1.0% of set value or ± 0.01 x U n Accuracy class of the operation Accuracy class of the operation is 1.0 Configuration data Task execution interval (Relay Configuration Tool): 40 ms at the rated frequency f n = 50 Hz Technical revision history Function block Technical revision MEVO3A B - Change C Event reason and event state in the event table changed as follows (an example): Event reason: U1 high warning U1 Event state: Reset High warning reset D Input data: Units removed from parameter names Warning and alarm outputs added Names of the voltage inputs changed: E U1_12 UL1_U12, etc. Added time-based threshold function: - a new value for Threshold select : Time interval - parameter Time interval added MEVO3B A - B Input data: Units removed from parameter names Names of the voltage inputs changed: C U1_12 UL1_U12, etc. See above: MEVO3A E 17