ENG-1990 — Page 277

LAND, PUBLIC WORKS AND UTILITIES

system at 400 kV to transmit power from the Castle Peak Stations to the various load centres was completed in 1986. This 400 kV network comprises two transmission rings. One ring, a primary ring encircling the New Territories, consists of 90 kilometres of double circuit overhead lines and four extra high voltage substations at Lei Muk Shue, Tsz Wan Shan, Tai Po and Yuen Long. The other ring consists of 22 kilometres of cable circuits linking the major substations at Tsz Wan Shan, Tai Wan and Lai Chi Kok.

For the HEC's supply areas, electricity is completely supplied from the Lamma Power Station. At the end of 1990, with two additional 125 MW gas turbines, the total installed capacity at the Lamma Power Station was 2 255 MW which consists of three 250 MW and two 350 MW dual coal/oil fired units, six 125 MW and one 55 MW gas turbines. There are plans to add a further 350 MW unit to Lamma in the early 1990s.

HEC's transmission system operates at 275 kV, 132 kV and 66 kV and distribution is effected mainly at 11 kV and 346 volts. With the exception of a small proportion of 132 kV overhead transmission lines, all supplies are transmitted and distributed by underground or by submarine cables. The supply is 50 hertz, 200 volts single phase and 346 volts three phase. Supplies at high voltage are also made available to consumers.

The transmission systems of CLP and HEC are interconnected by a cross-harbour link, thereby achieving cost savings to consumers through economic energy transfers between the two systems and a reduction in spinning reserve requirements. The interconnection, commissioned in 1981, now has a capacity of 480 MVA, with provision to increase it to 720 MVA, if required.

CLP's system is also interconnected with that of Guangdong General Power Company of China and about four million units of electricity are transmitted to Guangdong Province each day. This interconnection results in better utilisation of the company's generating plant during periods of low demand. Also, CLP has signed a contract with the China Merchants Steam Navigation Company Limited for the supply of electricity for a period of 10 years to the industrial zone of She Kou and the adjacent Che Wan area, both in Guangdong Province, China. The arrangement, which affords She Kou a reliable electricity supply without subsidy from Hong Kong consumers, is illustrative of the close co- operation on energy matters which has developed on both sides of the border.

On January 18, 1985, the Hong Kong Nuclear Investment Company (a wholly-owned subsidiary of CLP) and the Guangdong Nuclear Investment Company (wholly owned by the Chinese Ministry of Nuclear Industry) signed the Joint Venture Contract for the formation of the Guangdong Nuclear Power Joint Venture Company, to construct and operate a nuclear power station at Daya Bay in Guangdong Province.

The Daya Bay Nuclear Power Station will comprise two 900 MW pressurised water reactors which are scheduled for commissioning in 1992 and 1993. About 70 per cent of the power from the station will be purchased by CLP to meet part of the longer-term demand for electricity in its area of supply.

In May 1990, the government decided that the electricity supply voltage in Hong Kong should be upgraded from 200 volts single phase and 346 volts three phase to 220 volts single phase and 380 volts three phase, and that a Supply Voltage Advisory Committee be set up to advise on the implementation of voltage upgrading in the territory. The voltage upgrading is planned to be carried out in three phases and completed within seven years. Phase I conversion will cover existing installations in government buildings and will be completed within about 18 months. Phase II will cover Housing Authority buildings and is

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