SK827100-AS交流接触器模块
DECS-100监控感应到的发电机输出电压，并在以下情况下采取保护措施：检测到感测电压。在以下条件下检测到感测电压的损失。
•感应电压小于额定电压的50%（单相或三相感应）。
•出现任何相位的总损耗（三相感应）。
•任何相位（线对线）和三相平均值之间的电压差超过20标称百分比（三相感应）。
可通过BESTCOMS软件调整0至25秒的时间延迟。这会延迟保护动作，以便在不感应B相发电机电流的应用中允许磁场强制。这个默认时间延迟设置为10秒。
BESTCOMS软件允许选择两种保护措施中的一种，以防止传感丢失。要么可以选择完全关闭或切换到手动模式。如果选择停机且发生传感丢失，则前部的发电机传感丢失指示灯
面板和BESTCOMS灯中，继电器输出关闭，DECS-100在可调时间延迟到期。发电机感测丢失后DECS-100通电时停机时，发电机感应指示灯将点亮5秒钟。然而，如果损失传感条件仍然存在，DECS-100在软启动之前不会因传感丢失而关闭时间延迟和感测时间延迟的丢失到期。
如果选择了手动切换，并且发生传感丢失，继电器输出关闭，DECS-100在可调时间延迟到期后，转换到手动操作模式。
DECS-100将保持此操作模式
直到通过BESTCOMS切换。在选择“转移到手动”之前，打开失去感测，需要确定适当的手动（FCR）模式设定点水平不适当的励磁水平可能导致设备严重损坏。
当频率降至12赫兹以下或发电机短路时，此功能将禁用检测到条件。当B相CT电流超过3时，确定发电机短路乘以每单位值。在软启动时间内，传感关闭或传输丢失未激活。磁场过电压（过励磁停机）
现场过电压条件可被配置（在BESTCOMS中）以关闭DECS-100继电器输出，禁用DECS-100，启动两个动作，或不启动任何动作。当场电压增加时在10秒的固定持续时间内，高于可调电压电平设定值时，DECS-100启动所选操作。
如果DECS-100配置为关闭继电器输出，则磁场过电压条件将点亮前部面板和BESTCOMS过励磁停机指示器，并关闭端子AL1处的继电器输出和AL2。
如果DECS-100配置为硬件关机，则在10秒延时到期后，现场过电压条件将禁用DECS100。当DECS-100在现场后通电时
过电压停机时，过励磁停机指示灯将点亮5秒钟。
The DECS-100 monitors the sensed generator output voltage and takes protective action if a loss of sensing voltage is detected. A loss of sensing voltage is detected during the following conditions. • The sensed voltage is less than 50 percent of the rated voltage (one-phase or three-phase sensing). • A total loss of any phase occurs (three-phase sensing). • The voltage difference between any phase (line-to-line) and the three-phase average exceeds 20 percent of nominal (three-phase sensing). A time delay of 0 to 25 seconds is adjustable through BESTCOMS software. This delays the protective action in order to allow field forcing in applications that do not sense B-phase generator current. The default time delay setting is 10 seconds. BESTCOMS software allows the selection of one of two protective actions for a loss of sensing. Either a complete shutdown or a transfer to Manual mode may be selected. If shutdown is selected and a loss of sensing occurs, the Loss of Generator Sensing indicator on the front panel and in BESTCOMS lights, the relay output closes, and the DECS-100 shuts down after the adjustable time delay expires. When the DECS-100 is powered up following a loss of generator sensing shutdown, the Loss of Generator Sensing indicator will light for five seconds. However, if the loss of sensing conditions still exists, the DECS-100 will not shut down due to loss of sensing until the soft-start time delay and the loss of sensing time delay expires. If transfer to Manual is selected and a loss of sensing occurs, the relay output closes, and the DECS-100 transfers to the Manual mode of operation after the adjustable time delay expires. The DECS-100 will remain in this mode of operation until switched via BESTCOMS. Prior to selecting transfer to Manual on loss of sensing, it is necessary to determine an appropriate Manual (FCR) mode setpoint level to be transferred to. An inappropriate excitation level could result in severe damage to equipment. This function is disabled when the frequency decreases below 12 hertz or when a generator short circuit condition is detected. A generator short-circuit is determined when the B-phase CT current exceeds three times the per unit value. Loss of sensing shutdown or transfer is not active during the soft-start time. Field Overvoltage (Overexcitation Shutdown) A field overvoltage condition can be configured (in BESTCOMS) to close the DECS-100 relay output, disable the DECS-100, initiate both actions, or initiate neither action. When the field voltage increases above the adjustable voltage level setpoint for the fixed duration of 10 seconds, the DECS-100 initiates the selected action. If the DECS-100 is configured to close the relay output, a field overvoltage condition will light the front panel and BESTCOMS Overexcitation Shutdown indicator and close the relay output at terminals AL1 and AL2. If the DECS-100 is configured for hardware shutdown, a field overvoltage condition will disable the DECS100 after the 10 second time delay expires. When the DECS-100 is powered up following a field overvoltage shutdown, the Overexcitation Shutdown indicator will light for five seconds.
