IEEE Std 741 pdf free download

IEEE Std 741 pdf free download.Criteria for the Protection of Class 1 E Power Systems and Equipment in Nuclear Power Generating Stations.
3. Definitions, abbreviations, and acronyms
3.1 Definitions
For the purposes of this document, the following terms and definitions apply. The IEEE Standards Dictionwy
Online’ and IEEE C37.IOOTM [139] should be consulted for terms not defined in this clause.
anabtical limit: A limit ot’a measured or calculated variable, established by the analysis to ensure that a safety limit is not exceeded.
anticipated overloads: Those values of motor current in excess of motor nameplate rating that are expected to be realized during valve actuation due to the varying torque nature of the load.
degraded voltage relay (DVK): Undervoltage relays; part of’ the (second level of) undervoltage protection (with time delay) provided to protect the Class I E equipment from damage or becoming unavailable upon transfer to an alternate source (US. NRC Branch Technical Position, PSB-l [B 161). These protective relays monitor the Class I E safety bus voltages and automatically initiate the disconnection of otl’.site power whenever the voltage setting and time delay limits have been exceeded.
duty cycle of a valve actuator: The duty cycle of a valve actuator consists of the number of valve strokes needed for its intended service. Plant operation or testing may require successive stroking of the valve.
duty cycle time of a valve actuator: The time required for a valve to complete one stroke multiplied by the duty cycle.
DVR dropout setting: The voltage setpoint of the degraded voltage relay (DVR) that causes the relay to actuate and automatically disconnect offsite power, after the DVR voltage limit and the DVR time delay limit is reached. Also, the minimum voltage at which all Class 1 E loads are capable of starting and running indefinitely.
D’R reset setting: The voltage value that causes the degraded voltage relay (DVR) to reset following relay initiation. If this voltage value is reached prior to DVR timeout, it will prevent automatic disconnection of offsite power.
LVR dropout setting: The voltage setpoint of the loss of voltage relay (LVR) that causes the relay to actuate and automatically disconnect offsite power after the LVR voltage limit and LVR time delay limit is reached. Also, minimum voltage at which all Class I E loads are capable of running thr a defined period of time.
minimum required grid voltage: The minimum switchyard voltage required to maintain an operable preferred otisite power supply such that the supply can perform its intended safety function per GDC-17. This requires the ofl’site supply to have sufficient capacity and capability to perform its intended function, including the ability to maintain voltage while accepting the accident loads. It also requires the supply to safety-related loads without causing the DVR to time out and trip thereby causing separation from the ofisite power supply.
valve actuator motor nominal current: The current that the motor is rated to carry for the duration of its rated duty, commonly known as the motor nameplate current.
valve actuator motor nominal torque: The torque that corresponds to the valve actuator nominal current.
valve stroke: Complete travel distance of a valve from either fully open to fully closed position, or vice-versa.IEEE Std 741 pdf free download.