UV2PTUV can be set to measure phase-to-earth fundamental value, phase-to-phasefundamental value, phase-to-earth true RMS value or phase-to-phase true RMSvalue. The choice of the measuring is done by the parameter ConnType. Thevoltage related settings are made in percent of base voltage which is set in kV phase-to-phase voltage. This means operation for phase-to-earth voltage under:(%) ( )3U UBase kV< ×EQUATION1429 V1 EN (Equation 43)and operation for phase-to-phase voltage under:U (%) UBase(kV)< ×EQUATION1990 V1 EN (Equation 44)7.1.2.1 Measurement principleDepending on the set ConnType value, UV2PTUV measures phase-to-earth or phase-to-phase voltages and compare against set values, U1< and U2<. The parametersOpMode1 and OpMode2 influence the requirements to activate the STARToutputs. Either 1 out of 3, 2 out of 3, or 3 out of 3 measured voltages have to belower than the corresponding set point to issue the corresponding START signal.To avoid oscillations of the output START signal, a hysteresis has been included.7.1.2.2 Time delayThe time delay for the two steps can be either definite time delay (DT) or inversetime delay (IDMT). For the inverse time delay three different modes are available:• inverse curve A• inverse curve B• customer programmable inverse curveThe type A curve is described as:kt U UU= < -æ öç ÷<è øEQUATION1431 V1 EN (Equation 45)The type B curve is described as:Section 7 1MRK 505 208-UEN BVoltage protection214Technical reference manual
