HT PT
Connection diagram, Working Principle, Technical Parameters and Types.
1 - Full form of HT 11/33 KV PT:
HT: High Tension - 11 KV or 33 KV power supply .
PT: potential TranSformer - It is used for converting high voltage into 110V low voltage for
measuring the high voltage.
2 - What is the HT PT and Types :
A potential or voltage transformer is used for measuring the high voltage of the HT line or HT panel. It is called an instrument transformer. It converts high voltage (11, 33 KV) - into low voltage (110 Volt). These 110 voltages can be measured by voltmeter and they can be used easily in protection relay and another control circuit.
Types of PT :
According to application and range of voltage, the PT can be classified into different types:
- HT PT. It is designed as per voltage.
- Indoor Type: Indoor type PT is used in HT panels inside substations or industries which is used in 11 KV or 33 KV high voltage. It is made of an epoxy cast resin material. It is known as a dry type potential Transformer.
- Outdoor Type: it is used in a substation open above area 33 KV for transmission and
distribution.
3 - HT PT connection diagram:
4 - Working Principle:
It works as a normal transformer. it depends on the base of electromagnetic induction. It is a static
electrical device.it converts the high voltage into a low voltage at the same frequency.
The primary winding of CT is connected to the input HT supply 11KV or 33 KV than alternating flux generated
into laminated core according to Faradays law due to flux, induced emf will generate on secondary.
5 - Technical Parameters of PT:
| Sr.No. | Parameters | Value |
|---|---|---|
| 1 | Primary Voltage (V) | 11 KV to 36 kV |
| 2 | Insulation Rating (kV) | Up to 36/70/170 KV |
| 3 | PT Accuracy Ratings | .1,.2,.5, 1, 3, 5 |
| 4 | Secondary Voltage (V) | 110V/RT3, 110V/3 |
| 5 | Class of Insulation | Class A |
| 6 | Type of Earthing | E-N |
| 7 | Rated Burden (VA) | Up to 500VA |
