ELECTRIC GRID IN INDIA

What is an electrical grid ?

A grid is an interconnected network of transmission lines and substations hooked on to generating stations on the one hand and load centres on the other. The generating stations, put together, supply the electricity demand through the transmission lines; the load centres or distribution companies then draw the power from the lines and wheel it to consumers. The basic premise for the stability of the grid is that load and generation must be balanced at all times to prevent a failure.

The flow of electricity through the lines should ideally not exceed the rated capacity; otherwise the lines could trip due to an overload. For grid operators, one of the prerequisites is to ensure that there is adequate redundancy in the system so that the possible tripping of one line does not lead to a cascading event that can potentially impact operations of the grid as a whole.

Components of a grid

A grid consists of three main components:

1. power stations that produce electricity from fossil fuels (coal, gas) or non-combustible fuels (hydro, nuclear, wind, solar);
2. transmission lines that carry electricity from power plants to demand centers;
3. transformers that reduce the voltage so that distribution lines carry power for final delivery.

Functioning and Stability

All generating stations are expected to inject power as per schedules declared by them to the grid operator while all load centres or distribution utilities are expected to draw power as per the drawal schedule given by them to load despatch centres.

Stablity of the grid

This is done by monitoring the grid frequency, an index that shows whether power is being supplied and drawn as per schedule. The optimal frequency in India is pegged at 50 hertz, or cycles per second. The permissible frequency band for grid operations in India is 49.5Hz to 50.2Hz, as per the Indian Electricity Grid Code. The larger the grid size, the more stable it is deemed to be. At the same time, if a grid disturbance does happen, its scale could be larger for a larger grid.

The nature of network in India.

At present the northern, western, eastern and northeastern regions are integrally connected through AC (alternating current) transmission links to form what is called the 'NEW' grid. There is a free flow of power between these four regions. The southern region is hooked up with the rest of the country through HVDC (high voltage direct current) transmission links, which have constraints on wheeling capacity, thereby limiting the free flow of power from and to the southern region. India's current cumulative installed capacity is 205 gigawatts (1GW is 1,000MW).

Major problems plaguing the power transmission sector

1. During construction. The right of way (where to put the tower) problem is most severe because it is on somebody else’s land.
2. Availability of land to build substations. The availability and possibility of buying that land is also difficult.
3. Concerning the vendors. Because the construction is quite large, large number of vendors are needed. Sufficient numbers of vendors are not available.
4. The problems in realisation of money from the beneficiaries. The financial condition of distribution companies is not very good currently. So collection of money is difficult.
5. Grid collapse

While India has seen two major grid failures in the last 10 years, there have been several instances of grid collapses in other parts of the world. These include the Brazil-Paraguay blackout of 2009 that affected 87 million people, the Northeast blackout of 2003 in North America that affected some 55 million residents, the 2003 Italy blackout that hit another 55 million people, and the 2005 Java-Bali blackout, by which close to 100 million people were affected in Indonesia.

There can be two main reasons.

·         One is equipment failure due to reasons such as fog and pollution, as had happened when the northern grid collapsed in 2002.

·         The other, and more common, reason is when one or more constituents violate the grid code and overdraw in a big way from the grid, causing it to fail due to the imbalance in the power injection and drawal patterns.

Management of overdrawing

There cannot be physical control over excess drawal, only a financial penalty. In India, the grid frequency-linked penal measure is called the Unscheduled Interchange or UI rate. If the grid frequency drops, the UI rate shoots up, acting as a disincentive for discoms to overdraw when the frequency dips.

Northern states are repeat violators of the grid frequency norms, especially Uttar Pradesh, Haryana, Punjab, Jammu and Kashmir. The 'UI' penalty has failed to deter some of these states, which overdraw and then default on the 'UI' payment itself with the grid operators. UP, for instance, is known to routinely run up 'UI' bills of several hundred crores and delay the payments. The state has also taken advantage of a High Court order under which it does not pay the full UI penal rate.

Smart Grid

A "smart grid" is an electrical grid, which includes a variety of operational, and energy measures including smart meters, smart appliances, renewable energy resources, and energy efficiency resources. Electronic power conditioning and control of the production and distribution of electricity are important aspects of the smart grid.

Benefits of a smart-grid

1. The basic objective is that consumers should participate in the project. They should know what is happening in the power supply space. They should know how much they are actually consuming and paying. Presently, someone comes at some time for meter reading and the consumers have no clues, they just pay the bill. In the new system, a lot of intelligence is built into the meter.
2. Energy saving in a smart-grid set up. At least 15 to 20 per cent, which is huge. Smart-grid is the future. That is why we have invested in the project. Our objective is not to earn money but to ensure energy conservation and help improve the quality of life in the society.

The status of the smart-grid project and the roadmap ahead

The first project at Puducherry. All the features of smart-grid are there. The project is complete. One thousand four hundred smart meters have been installed. Any feature of smart-grid and it is there. Now, the government has planned similar projects at 14 other locations.

Progress

Smart -grid will be in various states. It is in the domain of distribution. It will not be in the network. Power grid Corporation is one consultant for these projects. In the transmission sector, a smart-grid is under implementation.

Plans for Smart grid

Out of the budgeted capital expenditure of Rs. 22,000 crore, 30 per cent will be Power grid money and the rest will be raised through line of credit and issue of bonds. Future plans

1. Shifting emphasis on commissioning.
2. Work on smart-grid and energy efficiency.
3. Venturing into products.
4. Altough a services company it has developed products such as smart meters and apertures.
5. The establishment of a research centre. The board is now setting up a lab facility.
6. Human  resources management. It is being ensured that at every level there is a leader. In this front, an academy is being set up called called Power grid Academy of Leadership at Manesar.
7. All the requirements till now were met through issuance of domestic bonds. It has shifted its attention to international bonds.