Discontinued

BGFT battery ground fault tracer

The main objective of a battery system is to provide standby and emergency power to operate industrial, consumer, commercial or protective devices. Some of these devices include emergency lighting units, uninterruptible power supplies, continuous process systems, operating controls, switchgear components and protective relays.

In emergency situations, it is essential that these devices be in proper operating condition. Failure of a DC system or the battery can result in operational failure of the devices connected to that system. System failure can lead to loss of revenue, damage to equipment, and/or injured personnel.

It is a common situation for a floating DC system to develop grounds within it. When a battery system is partially or completely grounded, a short circuit is formed across the battery and consequently may cause the protective device to fail to operate when needed.

The Battery Ground Fault Tracer transmits a 20 Hz signal through an energised or de-energised dc system. Feeder cables are tested for signal amplitude, which is inversely proportional to the fault impedance. Faults up to 399 kΩ are easily traced and isolated by clamping a direction-sensitive probe on the feeder cable and monitoring signal strength on the hand-held receiver. 

The Battery Ground Fault Tracer, which consists of a line operated transmitter and a portable, battery-powered receiver, determines fault magnitude and severity. The transmitter connects to the battery bus and station ground. Incorporating a resistance and capacitance bridge, the transmitter can be used to determine the fault’s magnitude and severity prior to tracking the fault. 

System capacitance can then be nulled from the measurement to prevent erroneous readings on the receiver. Immune to distributed noise in the system, Battery Ground Fault Tracer readings are unaffected by the presence of dc current and AC ripple up to 15 Amperes.

The transmitter can be left behind during tracing, which is performed quickly and easily using the hand-held receiver and clamp-on probe. The receiver provides digital display of signal amplitude, with a multiposition switch to adjust gain for optimal display resolution.

Customarily, utilities and industrial complexes have gone to great lengths to find ground faults within their battery systems. However, locating these battery grounds proves to be a very elusive and time-consuming process. The traditional ground fault location method involves sectionalising, or interruption of, DC branches to isolate the ground fault. Sectionalising disables the system protection and has been known to cause inadvertent line and generator tripping. For this reason, many utilities have banned sectionalising. Until more recently, though, this had been the only method available to locate ground faults.