Capacitor coupled voltage transformer and its input voltage parameter determination
OwnerForoozan Ghassemiinventor
Life of this patent
Estimating the term…
Abstract
Accurate harmonic measurements on electrical power systems where the main instrument transformers are of the capacitor coupled voltage type (CVT type) is made possible by the provision of one or more current sensors (PQCS1, PQCS2). CVTs typically have a high voltage capacitor bank (CH) and a low voltage capacitor bank (CL). One or more current sensors (PQCS1, PQCS2) is/are positioned so as to measure capacitor current and from that the input voltage (Vin) of the CVT can be determined for each frequency.
Claims14
A method of determining parameters of an input voltage to a capacitor coupled voltage transformer which includes high voltage capacitor means and low voltage capacitor means connected across the input voltage, the method comprising:
- measuring the current flowing in at least one of said capacitor means, and
- from the measurements obtaining the required parameters of the input voltage,
- wherein the measuring step comprises separately measuring the current flowing in each of said high voltage capacitor means and said low voltage capacitor means, obtaining from said measured values the voltages across each of said capacitor means, and summing the said voltages to obtain parameters of the total input voltage.
A method of determining parameters of an input voltage to a capacitor coupled voltage transformer which includes high voltage capacitor means and low voltage capacitor means connected across the input voltage, which comprises measuring the current flowing in at least one of said capacitor means, and from the measurements obtaining the required parameters of the input voltage, in which the required parameters are the harmonic values of the input voltage.
A capacitor coupled voltage transformer comprising high voltage capacitor means and low voltage capacitor means arranged to be connected across an input voltage, current sensor means arranged to sense the current flowing in at least one of said capacitor means, and measurement means arranged to provide from the sensed current values a measurement of parameters of the input voltage, in which the parameters are harmonic values of the input voltage.
A capacitor coupled voltage transformer comprising;
- high voltage capacitor means and low voltage capacitor means arranged to be connected across an input voltage,
- current sensor means comprising first and second current sensors respectively to measure the current flowing in said high voltage capacitor means and in said low voltage capacitor means, and
- measurement means arranged to provide from the sensed current values a measurement of parameters of the input voltage.
Dependencies are inferred from the claim text.