Monitoring system for the capacitor batteries of a three-phase filter circuit
First Claim
1. A monitoring system for the capacitor batteries of a three-phase filter circuit having three filter legs connected in a Y-circuit configuration, the Y-circuit node being connected to a reference potential, each capacitor battery being of the type having a plurality of parallel legs, each leg having a plurality of sectional capacitors connected in series with respective fuses, adjacent ones of the sectional capacitors being coupled to one another, the system further comprising means for determining variations in the magnitude and phase of a fundamental frequency component of a zero current flowing from the Y-circuit node of the three-phase filter circuit to the reference potential, said variations being evaluated to identify defective ones of the sectional capacitors in a capacitor battery.
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Abstract
A system for monitoring the capacitor batteries of a three-phase filter circuit. Each capacitor battery is formed of a plurality of parallel legs each having a plurality of sectional capacitors which are connected in series with fuses. Adjacent ones of the sectional capacitors are coupled to one another. In a three-phase system, three capacitor batteries are coupled to one another in a Y-circuit configuration, the Y-circuit node being coupled to a reference potential, illustratively ground. The magnitude and phase of the fundamental frequency component of the current flowing from the Y-circuit node to the reference potential is monitored, variations therein being evaluated to identify defective sectional capacitors. Only variations in the Y-circuit node current which occur rapidly will trigger fault signals, thereby preventing false indications resulting from variations in temperature.
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8 Claims
- 1. A monitoring system for the capacitor batteries of a three-phase filter circuit having three filter legs connected in a Y-circuit configuration, the Y-circuit node being connected to a reference potential, each capacitor battery being of the type having a plurality of parallel legs, each leg having a plurality of sectional capacitors connected in series with respective fuses, adjacent ones of the sectional capacitors being coupled to one another, the system further comprising means for determining variations in the magnitude and phase of a fundamental frequency component of a zero current flowing from the Y-circuit node of the three-phase filter circuit to the reference potential, said variations being evaluated to identify defective ones of the sectional capacitors in a capacitor battery.
Specification