A Simple and Inexpensive Method for Accurately Measuring Stead-State and Transient High Voltages

This paper presents a simple method for accurately measuring voltages present on high-voltage systems during both transient and steady-state conditions without modifying the conditions producing the voltage to be measured. An electronic amplifier having high input resistance and negligible circuit loading provides adequate current to operate magnetic oscillograph galvanometers (or meters and relays) in proportion to the input voltage obtained from capacitance voltage dividers. These may be transmission line switching-transient voltages, voltages across circuit breaker contacts, static capacitor transient voltages, or neutral displacement voltages. Frequencies ranging from direct current to a hundred or more kilocycles are within the capability of the device, although the actual value, determined by the indicating or recording instrument which it actuates, may be limited to a few thousand cycles. Limitations and problems encountered in the use of capacitance potential dividers are also briefly discussed.