Dr Fahd Hashiesh, Fellow of the Institution of Engineering and Technology, and Technology Manager, ABB Ltd., UK, speaks on some of the latest technologies spurring the growth of grids and their relevance to the Indian context.
Disturbances and outages are common across the Indian power grid. How can power system simulations help? Are these solutions being used in India?
Power system simulations play an important role in overcoming disturbances. In fact the more offline studies that can be performed using different power system simulations, the less likely these disturbances might happen. But this should be based on real and accurate data. Sometime back, I saw lot of papers and journals published by Indian engineers demonstrating different fault and disturbance scenarios with respect to the grid´s behaviour. On the other hand, India started to install some PMUs (Phasor Measurement Units) at different locations of the grid which will help in gathering actual dynamic data that can be fed directly to the power system simulations to address the future grid requirements.
What are the latest developments in the field of Power Line Communications?
Unfortunately as far as I am aware, the development in the field of PLC is not as fast as other communication technologies. Actually, we need to be clear here about what voltage level we are talking about and for which application. Also the amount and type of data play a very important part. For domestic applications and low voltage level, the technology is growing very fast. However not all appliances are built to integrate with such technologies and manufacturers still prefer communication facilities such as Wi-Fi or Bluetooth.
This results in a limited number of applications. Moving towards the medium voltage side, the PLC technology is still limited with distance of transmission and coupling over transformers. Some companies have overcome the coupling issue. But a lot of research is still required.
This technology is being used widely for transmitting data for Internet and other applications such as IPTV & VoIP under BPL (broadband over powerline). For the High Voltage side or the transmission side, the technology is mature, but the preference today is towards deploying fibre connection for its simplicity and capabilities of transmitting data.
Could you give us some details on the recent advances in battery storage systems? How do these advances boost the development of renewable energy?
Renewable generation and storage form one integrated part. In other words, there is no way forward for renewable without proper storage capabilities. Lot of researches and pilot projects are in place now to test different size of storage mechanisms and the way of interaction with the grid. Also, storage will solve some other issues which the grid might face in the future, such as loss of system inertia.
What are the technological and application issues to be considered before the whole-scale implementation of wide-area monitoring, protection, and control systems?
Wide Area Monitoring Protection and Control Systems (WAMPAC) systems are not on-shelf products. Hence they are tailor-made according to the grid requirements. Deployment of WAMPAC happens in some key stages. First of all it´s about the optimum allocation of the PMUs (Phasor measurement units) which is the main pillar of the WAMPAC technology. A PMU is a transducer that converts three phase analog signal of voltage or current into precision time tagged positive sequence phasor measured at different locations. Best practices and research studies show that the PMUs can be installed at 1/5 to 1/3 of the total number of the grid busses to give a full observability about the system. The second step is to ensure the presence of a reliable and secure communication facility to link the PMUs with the data concentrator and the system protection centre, which is the brain for the WAMPAC.
The last step is for the grid operator to choose the application to implement. This can be only monitoring (WAMS), which might include active & reactive power measurement, angles between buses, rate of change of frequency, etc. or, using the full capability of the technology (WAMPAC) to imitate remedial actions (i.e. load shedding, generation rejection, islanding, etc.).
What are the key issues that over-stressed networks have to contend with when a dynamic & transient stability analysis has to be carried out?
In order to carry out a proper dynamic & transient stability analysis correct system dynamic data should be in place. PMUs can be used for this purpose.
Coming back to Smart Grids, what is the next big thing that´s coming out from this field?
It´s about the way we define the meaning of a Smart Grid. Are we talking about distribution, transmission or generation level? No doubt the next step is enhancement in energy storage and using more FACTS in the system.
Also the deployment of self-healing systems using the advent of WAMPAC is so close. Moving towards the consumer side, it will be about engaging the customer in deciding their load profile.
With specific reference to India, transmission & distribution losses continue to plague the domestic power industry. What can be done?
This is a long question to answer. To put it very simply, it is about employing the usage of FACTS (Flexible AC Transmission systems) at different location of the grid based on proper system studies.