Keeping the city switched on and safe

We're talking danger here. Words like 'high voltage' printed with bolt-of-lightning symbols warning us of severe or fatal physical jolts if we get too curious about the inner workings of equipment conveying power across Hong Kong.

Yet an electrical engineer would grin and gently shake his head when asked if he has suffered even a mild electric shock.

For part of the job is to ensure that the array of installations, substations, cables and other equipment are as safe as possible, and readily available at the flick of a switch or the gentle press of a remote control.

And we're talking big here too; a far cry from the microscopic challenges faced by electronics engineers. The paths of either discipline may sometimes cross in the field of power electronics where smaller components control huge currents.

Knowing your alternating current from your direct current may be all well and good, but electrical engineers are in the business of real power and are trained to harness and control this to meet Hong Kong's electricity demands.

Control comes in the form of transmitting this power through miles of overhead, underground and even submarine cables to substations before its voltage rating is transformed to make it compatible for use in our homes, transport facilities and practically everywhere.

'Without the heavy current of electrical engineering I think we'll all go back to the cave, but without electronics engineering we can't communicate [electronically] that easily or even reach the moon,' said Wong Kit-po, head of Hong Kong Polytechnic University's (PolyU) electrical engineering department and chairman of the electrical division at the Hong Kong Institution of Engineers (HKIE).

To give students considering becoming electrical engineers a perspective on the sheer size of the energy forces they would be dealing with, it is important to understand the vast differences in measurement compared to electronics.

Tai Tak-him, an engineer with the government's Drainage Services Department, which relies on huge motors to power water from the mainland to Hong Kong and in the treatment of sewage, said: 'It's about big currents; we deal with kilo-amperes - electronics engineering talks about micro-amperes or even smaller.

'But it's also about the production, generation and distribution and electrical engineering being applied to build the high-voltage systems to support the powering of water supply, buildings, hospitals, the MTR and KCR, and other facilities,' Mr Tai said.

Think of the humble switch. On the domestic or office wall it's a small device that opens, connects, closes or in some cases gradually raises or lessens the supply of power. On an industrial scale, such a switch and the mechanisms used to control it can be the size of a room, while a single electrical component is often taller than a man - hardly a mass-produced device, and one that requires teams of electrical engineers for it to be designed, built and maintained.

'Within an electrical substation there is so much equipment, like transformers, cables and switchgear with high voltage,' said Yung Kai-man, an asset manager at CLP Power Hong Kong with responsibility for power systems.

'We're talking big switches which are not operated manually. If anything goes wrong, the switches will carry out their designed duty to prevent a blackout. '

Electrical engineers take pride in how Hong Kong is not subject to the power outages experienced in certain other cities. They attribute this to such reasons as good planning, properly maintained equipment - and well-trained engineers.

Complex transmitters ensure MTR trains get enough electrical power to accelerate from station to station.

In turn, devices designed on electrical engineering principles ensure that that power is gradually reduced whenever the train is required to slow down or stop.

Research is being carried out at PolyU to enhance these systems we take for granted.

Engineers consider research a vital area. For those in the electrical field, it is needed not only to keep ahead of industrial and consumer demand, but in tackling the question of limited energy resources and finding alternative means of harnessing energy, be it through wind turbines, solar, water-generated power, fuel cells, the building of more efficient and eco-friendly systems, or more controversially how cleanly and safely fossil-fuelled or nuclear-powered facilities can be used to generate power.

CLP Power Hong Kong is one of the energy utilities that co-operate with PolyU in the field of research and training.

'There's a lot of co-operation between the institute and industry. When we have problems and issues we consult to see what innovative research they come up with and then apply it to the industry,' said Mr Yung, who is also the HKIE's electrical division chairman.

Professor Wong added: 'Every day power utilities need to schedule generators, depending on variation of demand. So technologies are being developed based on artificial intelligence to meet these demands.

'The use of fibre-optic sensors to build what we call a smart railway-sensor system to do conditioning monitoring of the train and the track is another project that is a good example of collaboration between PolyU and the KCRC.'

Professor Wong said the system was now at the R&D stage but would 'take a few years to go through all the international standard specifications'.

That may sound like a long time but, as Mr Yung said, such research was about giving engineers far more information than they already had to make the rail system ever more efficient and reliable.

This article is part of a series on engineering trends and development, produced in association with The Hong Kong Institution of Engineers. It is published on the last Saturday of every month