Power Grid and development in India

ST. THOMAS COLLEGE OF ENGINEERING & TECHNOLOGY

NEED OF FORMATION OF NATIONAL POWER GRID

ELECTRICAL ENGINEERING , 2ND YEAR , GROUP NO. - 02

SANDIPAN CHAKRABORTY – O6 SOUMESH CHAKRABORTY – 07 ARITRA CHATTERJEE – O8 RANOTROSH CHOWDHURY – 09

TRATHAGATA ROY CHOWDHURY – 10

INTRODUCTIONAn electrical grid is an interconnected network for delivering electricity from suppliers to consumers. It consists of generating stations that produce electrical power, high-voltage transmission lines that carry power from distant sources to demand canters, sometimes across international boundaries.

The job of the grid operator is to give operating instructions to the engineers in the field and ensure moment-to-moment power balance in the interconnected power system.

The country is geographically divided in five regions - Northern, Eastern, Western, North Eastern and Southern.

The northern grid spans through nine states, namely Punjab, Haryana, Rajasthan, Uttar Pradesh, Uttarakhand, Himachal Pradesh, Jammu Kashmir and Chandigarh. Eastern regions like West Bengal, Bihar, Jharkhand, Odisha and Sikkim.Maharashtra, Chhattisgarh, Goa, Madhya – Pradesh, Goa are connected by Western grid.Arunachal Pradesh, Nagaland, Assam, Meghalaya, Manipur, Mizoram and Tripura are connected by north eastern grid.

Tamil Nadu, Andhra Pradesh, Kerala, Karnataka and Pondicherry are connected by Southern grid.

The first four out these five regional grids are operating in a synchronous mode .

The Southern Region is interconnected with the rest of India grid through asynchronous links .This implies that quantum and direction of power between Southern Grid and rest of India grid can be manually controlled.

• Each of the five regions has a Regional Load Despatch Centre (RLDC) .To ensure integrated operation of the power system in the concerned region the RLDCs for North, East, West, South and Northeast regions are located at Delhi, Kolkata, Mumbai, Bangalore and Shillong respectively.

National control centre(1)

Regional control centre(5)

State control centre(34)

Every state has a State Load Despatch Centre (SLDC), which is the apex body to ensure integrated operation of the power system in the state.

As per the Electricity Act 2003, the Regional Load Despatch Centre monitor grid operations, exercise supervision and control over the inter-state transmission system .

Objective of power grid• Principle concerning national grid is total import equals

to total export. ∑import=∑export

• When supply is more than demand , power is wasted & this excessive power is transferred to another zone where shortage of power leads to power cuts.

• Restoring power in quickest possible time in the event of any natural disasters like super cyclone, flood etc. through deployment of Emergency Restoration Systems.

• Exercise supervision and control over the Inter-State transmission system.

• To facilitate private sector participation in transmission system through Independent Private Transmission Company / Joint Ventures.

• Geographically widely spread Indian Grid can facilitate interconnections with Neighbouring countries like India-Nepal, India-Bhutan, India-Bangladesh.

DEVELOPMENT OF POWER GRID

• HVDC is the future of power grids. AC will be replaced by high voltage DC which has less loss compared to AC.

• Flexible AC Transmission Systems, or FACTS provides a variety of benefits for increasing transmission efficiency .FACTS devices stabilize voltage, industry experience has shown FACTS devices to enhance transmission capacity by 20-40%.

• So-called high temperature superconducting (HTS) cables now under development, which can carry three to five times the power of conventional cables. The losses in HTS cables are also significantly lower than the losses in conventional lines.

• Wide area monitoring systems (WAMS) have many promising capabilities, one of which is line thermal monitoring.

• Some other ways-

Distributed generation/Micro grids.Underground distribution lines. Intelligent grid design (smart gridsvia automation) Fluctuations in grid frequency should be reduced & maintained in ranges 49.5-50.5 .

48.0

48.5

49.0

49.5

50.0

50.5

51.0

51.5

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01

02

03

04

05

06

07

08

09

10

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FREQUENCY SPECTRUM 2002 & 2003

<491

49.0 & < 49.59%

49.5 & < 50.589%

50.5 & More1%

<4982.0%

49.0 & < 49.57.2%

49.5 & < 50.58.8%

50.5 & More2.0%

BANGALORE

<360KV19%

360-380 KV16%380-420 KV

65%

>420 KV0%

BANGALORE VOLTAGE COMPARISION

ADVANTAGES

• ECONOMIC GENERATION

Many power stations all contribute to the total demand at busy times but at off peak times some can be shut down.

• CONVENIENCE

Very large power stations can be built at the most convenient locations, for example nuclear power stations can be built in areas where few people live, often at the coast where cooling water is easily available.

NTPC's Indira Gandhi Super 1,500 MW Thermal Power Project in Haryana.

• Less pollution

Pollution can be kept away from cities and large power stations can be built, which are more efficient. Power can be diverted to where it is needed, if there is high demand or a breakdown. Surplus power can be used to pump water up into reservoirs to be used to generate hydroelectric power when there is a peak in demand.

• If a power station needs to be turned off for any reason the consumers (houses and businesses) can continue to receive electricity from other power stations.

• Efficiency

any extra electricity in the system can be used to pump water up hill to be used later to generate electricity in a hydroelectric  power station.

• Other advantages

I. A single power station failure does not cut off any users.

II. National grid system can cope better with peak consumption hours occurring at different times at different locations in the area that the system covers.

III. Electricity can be used from any power station to meet demand in any part of the country.

DISADVANTAGES

• Some power is wasted heating the cables. Overhead power cables and their supporting towers are an eyesore in some places. If underground cables have to be used, they are much more expensive. Smaller local electricity generating projects, such as wind turbines and/or panels of solar cells, are unreliable compared to a national grid fed by major fixed power generating stations.

• Expensive, demands a lot of investment which is difficult for economically backward country such as India .

• Loads are primarily inductive (motors, large!) and will cause huge line drops, necessitating power factor correction devices (expensive).

• Remote village links will drag down the steady-state stability of the entire grid because of poor voltage profile (may cause frequent outage disturbances).

SMART GRID

The electrical grid is expected to evolve to a new grid paradigm—smart grid, an enhancement of the 20th century electrical grid.

• Function

1. The traditional electrical grids are generally used to carry power from a few central generators to a large number of users or customers. In contrast, the new emerging smart grid uses two-way flows of electricity and information to create an automated and distributed advanced energy delivery network.

2. uses digital technology

Grid disturbance

major grid disturbance causes largest blackout in India

EFFECT:•Transportation system were disrupted as railway trains were suspended.•Coal miners were stranded in mines as the blackout cut of electricity to elevators.•Air-conditioning was suspended, damaging the live hood of citizens.•Hospitals and factories had to operate emergency power system.•Exerted social & economical impacts

Restoration of Traction Supply after Grid Disturbance

STEPS TAKEN BY GOVERNMENT

• States shall take all necessary steps for strengthening and upgrading the State Load Despatch Centres and training of system operators.

There should be manpower capacity building by way of training and certification. • In a meeting taken by Secretary (Power) on 31.7.2012

at NLDC, it was decided that transfer capability of inter-regional links and other critical

links would be reviewed in consultation with CEA and CTU and implemented within 24 hours.

• Accordingly, assessment of Transfer capability based on SIL limits of the lines instead of stability limit evaluated from St Clair’s curve or thermal limit depending on the line length has been implemented and has been uploaded on the website of NLDC.

• 765 kV Bina-Gwalior-Agra-II (charged at 400 kV), was under shutdown at the time of disturbance. The line has since been restored on 7.8.2012.

CONCLUSION

• Modern economies are dependent on reliable and secure electricity services. Electricity makes an essential contribution to economic performance, international competitiveness and community prosperity.

• There is a clear shortage in terms of generation

and thus is not being able to meet the growing demand from the expanding Indian industry. Development of additional power plants must also be started.

• Ensuring communication to Load Despatch Centres from various transmission elements and generating stations and an extensive review and audit of the Protection Systems, would be a good step towards strengthening the power sector.

• Investment in technology that will reduce transmission losses.

Use of alternate sources of power generation must be encouraged.

• Establishment and operation of Regional and National Power Grids to facilitate transfer of power within and across the regions with Reliability, Security and Economy, on sound commercial principles. Investment in technology that will reduce transmission losses.

• Use of alternate sources of power generation must be encouraged.

• Establishment and operation of Regional and National Power Grids to facilitate transfer of power within and across the regions with Reliability, Security and Economy, on sound commercial principles.

• Evolved most effective Disaster Management System & Emergency Restoration System to minimize the impact of natural calamities.

• Evolved most effective Disaster Management System & Emergency Restoration System to minimize the impact of natural calamities

REFERENCES

• http://web.anl.gov/eesa/pdfs/brochures/PowerGridBrochure.pdf

• http://intranet.powergridindia.com/pn/downloads/Presentations/JS-MoP%20visit.ppt

• The Electric Power Grid: Today and Tomorrow-Massoud & Amin

• http://nrldc.org/docs/documents/Articles/GridMgmtOverview_Nov2007_ElectricalIndia.pdf

• Report of the Enquiry Committee on Grid Disturbance in Northern Region on 30th July 2012 and in Northern, Eastern and North-Eastern Region on 31st July 2012, Government of India, Ministry of Power, August 2012

Thank you