| 摘要 |
The present invention teaches a technique and provides for apparatus eminently useful for the continuous, simultaneous monitoring of the insulation quality of one or more pieces of high voltage ac electrical equipment, while the equipment is in service and connected to its normal high voltage source. The technique or method of the instant invention involves comparing a voltage, developed across a capacitive shunt at the capacitance tap of a transformer or bushing so equipped with a reference voltage taken from a voltage transformer or potential device connected to the same high voltage source. The effecting of the instant technique requires only a minimal amount of relatively inexpensive attendant centralized control equipment and is simply and easily placed into practice by, for example, such a centralized control unit which automatically computes and displays or prints the insulation power factor and/or capacitance, either continuously or at regular intervals for each piece of said ac electrical equipment being monitored by means of the instant invention such that, for example, alarms are sounded and contacts close when the power factor for any such piece being so monitored reaches preset limits. In addition, said central control unit may also make temperature corrections, compute averages, and indicate short-term and long-term trends.
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