Gas insulated switchgear (GIS) is an ideal system for installations in a limited space, if a high
availability is required. The new combined sensors are a perfect base for a wide range of
applications in protection, metering and control in the field of gas insulated substations.
The two most important functions performed in this combined sensor are the measurement of
current and voltage for protection, metering and conrrol.
The principle of Regowski coil is used for current measurement and of the capacitive voltage
divider for voltage measurement. Signals are converted to digital values and forwarded through
fiber optical cable to local control cubicles. This data acquisition is an important part of an
intelligent control and protection technique for GIS system.
This paper describes the design of a combined sensor, block diagram and Accuracy features of
such sensors. Good properties of the sensor permit its use for measurement, protection and control.
Moreover, insulating gas density and temperature, also enables evaluating and recording the
signals.
The simple layout of this combined sensor significantly improves dielectric capability in
comparison with conventional designs.
Measuring techniques have been developed to asses and improve measuring and dynamic
accuracy. Results show that the combined sensor is of better quality than known for conventional
inductive instrument transformers.
Combined current and voltage sensors for GIs fulfill the requirements for protection, metering and
control which add several advantages for the user.