초록 ▼

Apparatus for the detection of ground leakage in a normally ungrounded DC system includes a DC power supply and conductors from the supply for supplying power to a load connected to the DC system. There is an indicator connected between the DC system and a ground point such that a ground leakage in

Apparatus for the detection of ground leakage in a normally ungrounded DC system includes a DC power supply and conductors from the supply for supplying power to a load connected to the DC system. There is an indicator connected between the DC system and a ground point such that a ground leakage in the system closes a circuit to activate the indicator. With such activation, a pulser periodically interrupts the circuit to effectively generate an interrupted ground fault signal. Such signal is detected by a sensor located relative to the DC system such that an interrupted ground signal detected by the sensor locates the ground fault. Noise introduced into the pulse signal by the periodic interruption of the circuit during the ground fault occurrence is suppressed by the sensor.

대표청구항 ▼

Apparatus for the detection of low level ground leakage current in a normally ungrounded DC system in a multifeeder distribution system having a relatively high capacitive reactance and being associated with a relatively strong electromagnetic and electrostatic field, said system including a DC powe

Apparatus for the detection of low level ground leakage current in a normally ungrounded DC system in a multifeeder distribution system having a relatively high capacitive reactance and being associated with a relatively strong electromagnetic and electrostatic field, said system including a DC power supply, conductors from the supply for supplying power to a load connected in the DC system comprising a resistor element for connection across the DC power supply, a tapping point to the resistor element, a connector between the tapping point and a ground point such that a ground leakage current in the system completes a ground circuit, a normally closed relay between the tapping point and ground, a pulser for periodically opening and closing said relay while the ungrounded DC system remains substantially closed and operational, the opening and closing of said relay interrupting said ground circuit effectively thereby to generate a DC pulse interrupted ground fault signal and a magnetic sensor for location relative to the DC system for sensing said magnetic field changes and thereby said DC pulse interrupted ground fault signal and thereby providing for detecting the location of the low level ground leakage current in the relatively high capacitive reactance system, said DC system remaining substantially closed and operational during the ground leakage current detection, the pulse interruption rate being between about 6 to about 11 cycles per second.