UV2PTUV (27) can be set to measure phase-to-ground fundamental value, phase-to-phase fundamental value, phase-to-ground true RMS value or phase-to-phase true RMSvalue. The choice of the measuring is done by the parameter ConnType. The voltagerelated settings are made in percent of base voltage which is set in kV phase-to-phasevoltage. This means operation for phase-to-ground voltage under:(%) ( )3Vpickup VBase kV< ×EQUATION1606 V1 EN (Equation 71)and operation for phase-to-phase voltage under:Vpickup (%) VBase(kV)< ×EQUATION1991-ANSI V1 EN (Equation 72)When phase-to-ground voltage measurement is selected the functionautomatically introduces division of the base value by the square root ofthree.8.1.7.1 Measurement principleDepending on the set ConnType value, UV2PTUV (27) measures phase-to-ground orphase-to-phase voltages and compare against set values, Pickup1 and Pickup2. Theparameters OpMode1 and OpMode2 influence the requirements to activate the PICKUPoutputs. Either 1 out of 3, 2 out of 3, or 3 out of 3 measured voltages have to be lower thanthe corresponding set point to issue the corresponding PICKUP signal.To avoid oscillations of the output PICKUP signal, a hysteresis has been included.8.1.7.2 Time delayThe time delay for step 1 can be either definite time delay (DT) or inverse timeundervoltage (TUV). Step 2 is always definite time delay (DT). For the inverse time delaytwo different modes are available; inverse curve A and inverse curve B.The type A curve is described as:TDt Vpickup VVpickup= < -<ANSIEQUATION1431 V1 EN (Equation 73)Section 8 1MRK 506 335-UUS AVoltage protection296Technical manual
