IPM03A P0904HB工控模块卡件
电源管理469电机管理继电器4-45 4设定点编程4.6 S5热模型4简单来说，RTD偏置特性是测量定子温度的真实反馈。该反馈用作针对不可预见情况的热模型校正。由于RTD响应相对较慢，RTD偏置有利于校正和减缓电机加热。当电机加热相对较快时，在启动和重过载条件下需要热模型的其余部分。需要注意的是，仅RTD偏置功能不能产生跳闸。如果RTD偏置特性迫使热容量达到100%，则在发生过载跳闸之前，电机电流必须高于过载传感器。据推测，此时电机会因定子RTD温度而跳闸。图4-18:RTD偏置曲线最大定子RTD温度0 20 40 60 80 100-50 50 100 150 200 250 RTD偏置最大RTD偏置中心点RTD偏置最小热/冷=0.85额定温度=130 C绝缘额定值=155 C RTD热容量使用4-46 469电机管理继电器GE Power Management 4.7 S6电流元件4设定点编程4 4.7 S6电流元素4.7.1短路保护必须在打开此功能时拍摄。如果中断装置（接触器或断路器）的额定值不足以断开故障电流，则应禁用此功能。或者，可将该功能分配给辅助继电器，并将其连接，以使其跳闸能够断开故障电流的上游设备。如果打开，短路元件的功能如下。一旦Ia、Ib或Ic的幅值超过拾取电平×相位CT一次，达到“意向S/C跳闸延迟”规定的时间段，则发生跳闸。也可以启用备用跳闸功能。短路跳闸备用延迟应大于预期S/C跳闸延迟加上断路器清除时间。如果短路跳闸备份为“开”，且已启动短路跳闸，则如果电机相电流持续超过短路跳闸备份延迟时间，则会发生第二次跳闸。第二次跳闸指定给R2或R3，R2或R3将专用于上游断路器跳闸继电器。各种情况（例如，向电机或功率因数校正电容器的长线充电）可能会导致电机启动期间的瞬时涌入电流，其可能会在极短的时间内超过短路跳闸拾取电平。意向S/C跳闸延迟可按10ms增量调整。这种延迟可以根据应用程序进行微调，因此它仍然响应非常快，但可以克服正常的操作干扰。通常情况下，应尽可能快地设置意向S/C跳闸延迟，0 ms。
Power Management 469 Motor Management Relay 4-45 4 SETPOINT PROGRAMMING 4.6 S5 THERMAL MODEL 4 In simple terms, the RTD bias feature is real feedback of the measured stator temperature. This feedback acts as correction of the thermal model for unforeseen situations. Since RTDs are relatively slow to respond, RTD biasing is good for correction and slow motor heating. The rest of the thermal model is required during starting and heavy overload conditions when motor heating is relatively fast. It should be noted that the RTD bias feature alone cannot create a trip. If the RTD bias feature forces the thermal capacity used to 100%, the motor current must be above the overload pickup before an overload trip occurs. Presumably, the motor would trip on stator RTD temperature at that time. Figure 4–18: RTD BIAS CURVE Maximum Stator RTD Temperature 0 20 40 60 80 100 -50 0 50 100 150 200 250 RTD Bias Maximum RTD Bias Center Point RTD Bias Minimum Hot/Cold = 0.85 Rated Temperature=130 C Insulation Rating=155 C RTD Thermal Capacity Used 4-46 469 Motor Management Relay GE Power Management 4.7 S6 CURRENT ELEMENTS 4 SETPOINT PROGRAMMING 4 4.7 S6 CURRENT ELEMENTS 4.7.1 SHORT CIRCUIT Care must be taken when turning On this feature. If the interrupting device (contactor or circuit breaker) is not rated to break the fault current, this feature should be disabled. Alternatively, this feature may be assigned to an auxiliary relay and connected such that it trips an upstream device that is capable of breaking the fault current. If turned on, the Short Circuit element functions as follows. A trip occurs once the magnitude of either Ia, Ib, or Ic exceeds the Pickup Level × Phase CT Primary for a period of time specified by INTENTIONAL S/C TRIP DELAY. A backup trip feature may also be enabled. The SHORT CIRCUIT TRIP BACKUP DELAY should be greater than the INTENTIONAL S/C TRIP DELAY plus the breaker clearing time. If the SHORT CIRCUIT TRIP BACKUP is "On", and a Short Circuit trip has initiated, a second trip occurs if the motor phase current persists for a period of time exceeding the SHORT CIRCUIT TRIP BACKUP DELAY. It is intended that this second trip be assigned to R2 or R3 which would be dedicated as an upstream breaker trip relay. Various situations (e.g. charging a long line to the motor or power factor correction capacitors) may cause transient inrush currents during motor starting that may exceed the SHORT CIRCUIT TRIP PICKUP level for a very short period of time. The INTENTIONAL S/C TRIP DELAY is adjustable in 10 ms increments. This delay can be fine tuned to an application so it still responds very fast but rides through normal operational disturbances. Normally, the INTENTIONAL S/C TRIP DELAY is set as quick as possible, 0 ms.
