A hotstick instrument for estimation of the potential of an HVDC conductor

In 1989-90, New England Power Service Co. (NEPS) and Bonneville Power Administration (BPA) jointly sponsored the UHVDC live-line voltage-estimator project with three principal goals. These goals are: to develop a technology which would permit moderately accurate estimates of the DC potential of a UHVDC line without requiring an electrical connection to ground or any other reference point; to develop an instrument embodying this technology which could be applied by a lineman in the field and to demonstrate that the system functioned as expected; and to develop and incorporate in the instrument a technique for estimating the induced AC component of the potential. As demonstrated at the BPA outdoor test facility, the first goal has been fully met. It is demonstrated that a properly located field mill can determine the DC potential to better than 10% of full scale over a range from 0 to ± 500 kV, even in the presence of wind and corona. Solutions to the remaining pair of goals have been defined and an effort is now underway to develop a field-hardy engineering prototype of a production instrument