LAND, PUBLIC WORKS AND UTILITIES
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the voltage is being upgraded to 220 volts single-phase and 380 volts three-phase from 200 and 346 volts, respectively.
The two supply companies are investor-owned and do not operate on a franchise basis. The government monitors their financial arrangements through mutually- agreed scheme of control agreements. New agreements with CLP and HEC came into effect on October 1, 1993, and January 1, 1994, respectively. Both will last for 15 years. The agreements require each company to seek the approval of the government for certain aspects of their financing plans, including projected tariff levels.
Electricity for HEC's supply areas is supplied from the Lamma Power Station. At the end of 1995, total installed capacity at the Lamma Power Station was 2 955MW including a 350MW unit commissioned in late 1995. The government has also approved the installation by HEC of another 350MW unit at the Lamma Power Station in late 1997.
HEC's transmission system operates at 275kV, 132kV and 66kV and distribution is effected mainly at 11kV and 380 volts. Apart from a small proportion of 132kV overhead transmission lines, all supplies are transmitted and distributed by underground or submarine cables.
The Castle Peak Power Company Limited (CAPCO), which is 60 per cent owned by Exxon Energy Limited and 40 per cent by CLP, supplies electricity to CLP from its Castle Peak 'A' (1 752MW), Castle Peak 'B' (2 708MW) and Penny's Bay (300MW) power stations and two gas turbines at Tsing Yi (150MW), with the total installed capacity being 4 910MW. Tsing Yi 'A' and 'B' Power Stations (1 520MW) were decommissioned in stages over 1994 and 1995.
The government has approved CLP's installation of four 625MW blocks of additional generating capacity, the first two of which will be installed in a new power station at Black Point, Tuen Mun, in 1996 and 1997. The other two 625MW blocks will be split into four 312.5MW units and commissioned in 1998, 1999, 2000 and 2001. All will be fuelled by natural gas piped from the Yacheng 13-1 gas field off Hainan Island in China.
The associated transmission and distribution systems are wholly owned by CLP. Its transmission system operates at 400kV, 132kV and 66kV, and distribution is effected mainly at 33kV, 11kV and 380 volts. CLP has 196 primary and 9 041 secondary sub- stations in its transmission and distribution network.
An extra-high-voltage transmission system at 400kV was completed in 1986 to transmit power from the Castle Peak Stations to the various load centres. Currently it comprises a double-circuit overhead line system encircling the New Territories, underground cables and 11 extra-high-voltage sub-stations. Construction and planning work for reinforcement of the existing system is in progress.
The transmission systems of CLP and HEC are interconnected by a cross-harbour line. This provides emergency back-up and achieves cost savings to consumers. through economic energy transfers between the two systems and a reduction in the amount of generating capacity that needs to be kept as spinning reserve against the tripping of other units. The interconnection, commissioned in 1981, currently has a capacity of 720MVA.
CLP's system is also interconnected with that of the Guangdong Electric Power Holding Company (formerly named the Guangdong General Power Company) of