GE Multilin D30 Line Distance Protection System 5-2375 SETTINGS 5.9 TRANSDUCER INPUTS AND OUTPUTS5The dcmA output settings are described below.• DCMA OUTPUT H1 SOURCE: This setting specifies an internal analog value to drive the analog output. Actual values(FlexAnalog parameters) such as power, current amplitude, voltage amplitude, power factor, etc. can be configured assources driving dcmA outputs. Refer to Appendix A for a complete list of FlexAnalog parameters.• DCMA OUTPUT H1 RANGE: This setting allows selection of the output range. Each dcmA channel may be set inde-pendently to work with different ranges. The three most commonly used output ranges are available.• DCMA OUTPUT H1 MIN VAL: This setting allows setting the minimum limit for the signal that drives the output. Thissetting is used to control the mapping between an internal analog value and the output current. The setting is enteredin per-unit values. The base units are defined in the same manner as the FlexElement base units.• DCMA OUTPUT H1 MAX VAL: This setting allows setting the maximum limit for the signal that drives the output. Thissetting is used to control the mapping between an internal analog value and the output current. The setting is enteredin per-unit values. The base units are defined in the same manner as the FlexElement base units.The DCMA OUTPUT H1 MIN VAL and DCMA OUTPUT H1 MAX VAL settings are ignored for power factor base units (i.e. ifthe DCMA OUTPUT H1 SOURCE is set to FlexAnalog value based on power factor measurement).Three application examples are described below.EXAMPLE: POWER MONITORINGA three phase active power on a 13.8 kV system measured via UR-series relay source 1 is to be monitored by the dcmA H1output of the range of –1 to 1 mA. The following settings are applied on the relay: CT ratio = 1200:5, VT secondary 115, VTconnection is delta, and VT ratio = 120. The nominal current is 800 A primary and the nominal power factor is 0.90. Thepower is to be monitored in both importing and exporting directions and allow for 20% overload compared to the nominal.The nominal three-phase power is:(EQ 5.28)The three-phase power with 20% overload margin is:(EQ 5.29)The base unit for power (refer to the FlexElements section in this chapter for additional details) is:(EQ 5.30)The minimum and maximum power values to be monitored (in pu) are:(EQ 5.31)The following settings should be entered:DCMA OUTPUT H1 SOURCE: “SRC 1 P”DCMA OUTPUT H1 RANGE: “–1 to 1 mA”DCMA OUTPUT H1 MIN VAL: “–1.247 pu”DCMA OUTPUT H1 MAX VAL: “1.247 pu”With the above settings, the output will represent the power with the scale of 1 mA per 20.65 MW. The worst-case error forthis application can be calculated by superimposing the following two sources of error:• ±0.5% of the full scale for the analog output module, or• ±1% of reading error for the active power at power factor of 0.9For example at the reading of 20 MW, the worst-case error is 0.01 20 MW + 0.207 MW = 0.407 MW.EXAMPLE: CURRENT MONITORINGThe phase A current (true RMS value) is to be monitored via the H2 current output working with the range from 4 to 20 mA.The CT ratio is 5000:5 and the maximum load current is 4200 A. The current should be monitored from 0 A upwards, allow-ing for 50% overload.The phase current with the 50% overload margin is:NOTEP 3 13.8 kV 0.8 kA 0.9 17.21 MW= =P max 1.2 17.21 MW 20.65 MW= =P BASE 115 V 120 1.2 kA 16.56 MW= =minimum power 20.65 MW–16.56 MW------------------------------ 1.247 pu, maximum power 20.65 MW16.56 MW--------------------------- 1.247 pu= =–= =0.005 1 1– – 20.65 MW 0.207 MW=
