The timer calculates the start duration value START_DUR, which indicates thepercentage ratio of the start situation and the set operation time. The value isavailable in the monitored data view.Blocking logicThere are three operation modes in the blocking functionality. The operation modesare controlled by the BLOCK input and the global setting Configuration/System/Blocking mode which selects the blocking mode. The BLOCK input can becontrolled by a binary input, a horizontal communication input or an internal signalof the IED program. The influence of the BLOCK input signal activation ispreselected with the global Blocking mode setting.The Blocking mode setting has three blocking methods. In the "Freeze timers"mode, the operation timer is frozen to the prevailing value. In the "Block all"mode, the whole function is blocked and the timers are reset. In the "BlockOPERATE output" mode, the function operates normally but the OPERATE outputis not activated.The “Freeze timers” mode of blocking has no effect during the“Inverse reset” mode.4.5.2.5 Timer characteristicsThe operating curve types supported by PHPTUV are:Table 393:Supported IDMT operate curve typesOperating curve type(5) ANSI Def. Time(15) IEC Def. Time(21) Inv. Curve A(22) Inv. Curve B(23) Programmable4.5.2.6 ApplicationPHPTUV is applied to power system elements, such as generators, transformers,motors and power lines, to detect low voltage conditions. Low voltage conditionsare caused by abnormal operation or a fault in the power system. PHPTUV can beused in combination with overcurrent protections. Other applications are thedetection of a no-voltage condition, for example before the energization of a highvoltage line, or an automatic breaker trip in case of a blackout. PHPTUV is alsoused to initiate voltage correction measures, such as insertion of shunt capacitorbanks, to compensate for a reactive load and thereby to increase the voltage.Section 4 1YHT530004D05 DProtection functions478 615 seriesTechnical Manual
