ZONE FAULT DETECTION METHOD AND SYSTEM FOR ELECTRIC VEHICLE CHARGING SYSTEMS

摘要

A system for detecting faults in an electric vehicle charging system includes an electric vehicle supply equipment (EVSE) coupled to an electric vehicle via a cable. The EVSE includes a first charging circuit interrupting device (CCID) configured to detect faults at let-go levels between an ungrounded conductor in the cable and an external (or unintended) ground. The first CCID is also configured to detect faults above leakage current levels between a chassis of the vehicle and a power storage device of the vehicle. A second CCID is included in the cable or the vehicle to detect faults at let-go levels between an ungrounded conductor in the cable and the chassis. The system maintains grounding continuity between the electric vehicle and ground. The system thus provides protection at let-go levels while allowing a leakage current in the vehicle to be detected at a higher level for nuisance trip avoidance.

主权项

1. A system for detecting faults in an electric vehicle charging system, the system comprising:
an electric vehicle supply equipment (EVSE); a cable for electrically coupling the EVSE to a power storage device located in an electric vehicle, the cable including a first ungrounded cable conductor and a second ungrounded cable conductor each conducting a respective current between the EVSE and the power storage device to charge the power storage device, the cable further including a grounded cable conductor for conducting electrical current from the vehicle to a ground at the EVSE; and a first charging circuit interrupting device (CCID) at the EVSE, the first CCID being configured to monitor a current differential between the current conducted on the first ungrounded cable conductor, the current conducted on the second ungrounded cable conductor, and a first portion of the current conducted on the grounded cable conductor, the EVSE being configured such that a second portion of the current conducted on the grounded cable conductor bypasses the first CCID.