Types of High Voltage Insulation

In order to deliver high voltage electricity to consumers, good insulation must be used to ensure that electrical energy is not lost and safety is always present. Generally there are four types of electrical high voltage insulations available. There is gas insulation, liquid insulation, solid insulation and vacuum insulation. All four have their own unique characteristics, have their advantages and disadvantages.

World Electricity Consumption

Example of Gas Insulated High Voltage Apparatus

1) The picture below shows ABB ZX2 33kV switchgear used in some TNB Substation. 

ABB ZX2 Double Bus Gas Insulated Switchgear

2) Next one is an SF6 Ring Main Unit Switchgear. The picture was taken when I was doing preventive maintenance in Pencawang Elektrik Padat D/O Bungalow in Balik Pulau, Pulau Pinang.

F&G SF6 Ring Main Unit Switchgear in Pencawang Elektrik DO Bungalow in Balik Pulau

3) Below is the picture of 11kV Pelka Imalat Vacuum Circuit Breaker (VCB) in Bayan Bay Main Distribution Substation. The picture was taken when I did a switching for a breakdown nearby.

Pelka Imalat 11kV Vacuum Circuit Breaker

Example of Liquid Insulated High Voltage Apparatus

1) Below is the picture of 11kV 750kV Transformer taken from Kuarters TNB 'B' Substation in Bayan Baru. The winding of the transformer is immersed in Hyrax transformer oil which acts as insulation

750kVA 11kV/0.433kV Hermetically sealed Transformer

 2) Next is the picture of winding inside a 750kVA 11kV/0.433kV Hermetically sealed Transformer. The winding and accessories shown are all immersed in oil insulation

Inside 11kV/0.433kV 750kVA Transformer

3) Below is the conservator tank for a 90MVA 132kV/33kV. The picture was taken during our visit to Malaysian Transformer Manufacturing (MTM) factory in Hulu Klang. See how huge it is compared to a person standing next to it.

Conservator Tank for 90MVA 132kV/33kV Transformer

Example of Solid Insulation in High Voltage Apparatus

1) This is the picture of 33kV Aerial Bundle Cable (ABC) Straight Through Joint. The joint is put on a tray fitted on a 10 meter spun concrete pole. The picture was taken when I was on attending a fault between PMU Sungai Kecil and SSU NTPM in Nibong Tebal, Pulau Pinang. The insulation is based on polyethylene products.

33kV ABC Straight Through Joint

2) Next is the picture of 11kV Premoulded Underground Straight Through Joint. This picture was taken when I attended a breakdown somewhere in 2008. The insulation used is resin and plastic. The resin is in liquid form at first and it hardened to solid once the resin colds down.

11kV Single Core Premoulded Straight Through Joint

3) The picture below shows an 11kV Termination Joint on an Oil Link Unit switchgear. The orange colour covers is the cable sleeves which limit the high voltage stress of the cable termination. It is made from polyethylene. The picture was taken in 2006 when I was having my final year practical in TNB Distribution Banting.

11kV Termination Joint