Calculation and measurement of field parameters during live-line maintenance

The authors discuss the application of the charge simulation method (CSM) for calculation of the electric field and induced currents during live-line maintenance operations on a 330 kV line using insulating ladders. Several cases are considered, including the effect of orientation of the ladder and situations with damaged suspension insulators. Calculated field quantities include the electric field strengths and currents induced in the worker´s body. The CSM described can include cases with floating electrodes (insulator caps). The calculated results for field values along the ladder are still sufficiently accurate even when many insulators in a string are damaged. The engineering accuracy of the computational method was demonstrated through comparisons with measured data, determined using a small field probe. Results obtained are useful in identifying situations which may not be sufficiently safe for conducting live-line maintenance