Bushing failures are considered as one of the major causes for transformer outages. Historically bushings were tested off-line to measure the capacitance and the dissipation / power factor.

The Bushing Monitor ZVCM-1001, which is an extension package to the MTE HYDROCAL family, is a permanently installed on-line bushing monitoring system. It continuously measures up to six leakage currents, tests the power factor and capacitance values and monitors the condition of bushings, CCVT`s 1) and free-standing CT`s.

This system incorporates three measurement modes for standard and two for optional configurations:

Standard configuration with 6 current inputs:
  • Sum of three current test
  • Adjacent phase reference test
  • Phase comparison
Optional configuration with 3 voltage and 3 current inputs:
  • Reference test (3 bushings and 3 CCVTs)
Optional configuration with 6 voltage inputs:
  • CCVT Reference test (6 CCVTs )

The bushing sensors / adapters are connected to the capacitor taps designed for all types of bushings to allow measurement of the leakage current up to 140 mA AC.

The adapters are designed for bushings with grounded and undergrounded capacitor taps. The adapter is designed to prevent a voltage developing on the equipment, in case that the sensor becomes disconnected from the bushing monitoring system.

The Bushing Monitor ZVCM-1001 (joint development with ZTZ services) communicates directly with HYDROCAL 1005 and 1008 units and in conjunction with these units, it offers a complete transformer and bushing monitoring system in one package.