Battery systems are not electrically connected to the cabinets or racks supporting them. The cabinets and racks are connected to Earth ground, if current is present on the ground cable then a ground fault exists. BTECH’s system utilizes a precise, specialized custom current transducer to detect current leakage. The ground wire runs through the Current Transducer (CT), which is connected to the BGM-500, and the system continuously measures current flowing to ground. If the BGM-500 detects current above a configurable threshold value, it indicates a ground fault alarm. Depending on the alarm behavior configuration, the alarm either latches until cleared manually or clears when alarm conditions are corrected and ground current returns below alarm threshold value. Ground fault alarms can be triggered by positive or negative current, so the CT direction doesn’t affect the functionality of the BGM-500.
Battery Room Safety
Battery system ground faults are a dangerous and potentially catastrophic DC plant condition, if left undetected several things can happen:
- Unintended grounds can expose field service personnel to electric shock.
- Ground fault conditions can lead to battery system overheating and catastrophic failure.
- Battery system discharges with a ground fault present can exacerbate the condition and can lead to a dangerous thermal condition and fire.
- Battery system life can be severely limited.
- Battery capacity is reduced.