Designing a Voltage Sensor for the Diagnostic System of 110 kV Overhead Power Line Suspension Insulation

Abstract

The problem of promptly finding faulty insulator strings of 110 kV overhead power lines is addressed. The capacitances of PS-70E glass insulators in their new (delivered) state and in the state destroyed as a result of electric breakdown are measured. The residual dielectric strength and capacitance of destroyed insulators as a function of the glass part's grain size are investigated. An insulator string model is developed based on the system of nodal potential equations in matrix form, using which the availability of damaged insulators in the string can be taken into account. A method for remotely monitoring the state of multicomponent suspension insulation is proposed, which is based on recording a change in the capacitance of an insulator string when a faulty element appears in it. The proposed method implies the fitting of each insulator string with its own device (sensor) for monitoring the voltage across the capacitive impedance connected in series with the insulator string. The capacitive voltage sensor design, using which the described system can be implemented, has been developed. Supposedly, the sensors are to be connected via a wireless communication channel with the data acquisition center, in which a conclusion on whether a fault is contained in the insulation is drawn proceeding from the measured change of voltage. The parameters of the proposed sensor were calculated, based on which an operating prototype sensor has been constructed. The newly proposed voltage sensor design has a number of essential advantages over similar devices.