^ That can also be a weakness, as seen in the great blackout in the Northeast a few years ago. One fault rippled through to several states and across to Canada.
Nope. The northeast (of North America, for those who don't know where we are talking about) has a different power system then HK.
The northeast has the power grid interconnected to aid the demand and supple balancing. If there is a certain areas and times require a large demand of power (like during the summer when a/c is popular), but the local power plant can't supply so much. The system will draw power from others to fill in the need. Or if there is an excess of supply in certain location, it will send the excess to somewhere it needs and reduce the power generated. In other word, the system also help to reduce the amount of waste electric energy generated which can't be recycled. The pros are it help to balance supply and demand, as well as better generation management. The cons are, as we had seen, since the all the power plants are interconnected in a grid as series, once one line fails, everyone else goes down at the same time.
The interconnection in HK are mainly for emergency purpose only, and have minimum transfer over electricity to control the supply/demand or optimize use of resources. On a day to day basis, CLP and HK Electric doesn't transfer any electricity between each other. HKI and Lamma use HK Electric generated power exclusively; all other locations uses CLP generated power. So if CLP failed, HKI and Lamma will still have electricity, but not in Kowloon, NT and other outlying islands. In such case, the interconnect will kick in and HK Electric will start transfer electricity across the harbour providing service in CLP's service area. So that the black-out situation won't happen.
In addition, HK Electric has transferred some its overhead high voltage wires over the mountains and country parks between south of HKI and north of HKI down inside the four underground tunnels instead as well.