The Timer calculates the start duration value START_DUR, which indicates thepercentage ratio of the start situation and the set operation time. The value is availablein the Monitored data view.Blocking logicThere are three operation modes in the blocking function. The operation modes arecontrolled by the BLOCK input and the global setting in Configuration/System/Blocking mode which selects the blocking mode. The BLOCK input can be controlledby a binary input, a horizontal communication input or an internal signal of theprotection relay's 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, but the OPERATE output is notdeactivated when blocking is activated. In the "Block all" mode, the whole function isblocked and the Timers are reset. In the "Block OPERATE output" mode, the functionoperates normally but the OPERATE output is not activated.The “Freeze timers” mode of blocking has no effect during the“Inverse reset” mode.4.4.2.5 Timer characteristicsThe operating curve types supported by PHPTUV are:Table 422:Supported IDMT operate curve typesOperating curve type(5) ANSI Def. Time(15) IEC Def. Time(21) Inv. Curve A(22) Inv. Curve B(23) Programmable4.4.2.6 ApplicationPHPTUV is applied to power system elements, such as generators, transformers,motors and power lines, to detect low voltage conditions. Low voltage conditions arecaused by abnormal operation or a fault in the power system. PHPTUV can be used incombination with overcurrent protections. Other applications are the detection of ano-voltage condition, for example before the energization of a high voltage line, or anautomatic breaker trip in case of a blackout. PHPTUV is also used to initiate voltagecorrection measures, such as insertion of shunt capacitor banks, to compensate for areactive load and thereby to increase the voltage.Section 4 1MRS758755 AProtection functions418 REC615 and RER615Technical Manual
