Fault detection system with leakage current detection

摘要

A fault detection system for a machine having a plurality of electrical conducting elements insulated from a frame ground of the machine is disclosed. The fault detection system may include a high voltage DC power source, a positive high voltage bus connected to a positive terminal of the high voltage DC power source and providing high voltage electrical power to the plurality of electrical conducting elements, and a negative high voltage bus connected to a negative terminal of the high voltage DC power source and returning high voltage electrical power from the plurality of electrical conducting elements. At least one of the positive and negative high voltage buses may be selectively connected through a plurality of switches to plural zones of the electrical conducting elements, with each of the plural zones being electrically connected in parallel, and selectively connected to the high voltage DC power source by one of the plurality of switches. A low voltage DC power source may be configured to form part of a leakage current detector selectively connected through each of the plurality of switches to each of the plural zones for detecting leakage current between an electrical conducting element and the frame ground.

主权项

1. A fault detection system for a machine having a plurality of electrical conducting elements insulated from a frame ground of the machine, the system comprising:
a high voltage circuit including a high voltage DC power source; a positive high voltage bus connected to a positive terminal of the high voltage DC power source and providing high voltage electrical power to the plurality of electrical conducting elements; a negative high voltage bus connected to a negative terminal of the high voltage DC power source and returning high voltage electrical power from the plurality of electrical conducting elements; at least one of the positive high voltage bus and the negative high voltage bus configured to be selectively connected through a plurality of switches to plural parallel zones containing subsets of the plurality of electrical conducting elements, with each of the plural parallel zones being electrically connected in parallel to the high voltage circuit, and selectively connected to the high voltage DC power source by one of the plurality of switches; a first low voltage DC power source configured to form part of a leakage current detector, the leakage current detector configured to be selectively connected through each of the plurality of switches to each of the plural parallel zones for detecting leakage current between an electrical conducting element contained within the zone and the frame ground; and a second low voltage DC power source configured to be isolated from the high voltage DC power source and connected between the positive and negative high voltage buses and referenced to the frame ground by two balancing resistors connected in series to form a voltage divider between the positive and negative high voltage buses, and the second low voltage DC power source being further configured to be used in a low voltage diagnostic test to detect a low voltage unbalanced condition between the positive high voltage bus and the negative high voltage bus with respect to the frame ground when a leakage current from one of the electrical conducting elements to the frame ground exceeds a threshold.