STATUS OF TRANSMISSION LINE AND EXPANSION PLAN IN NEPAL

S. Rajbhandari

Components of Power System

Electrical power system mainly consist of three systems or components:

Generating system Transmission system Distribution system

Generating system consists of generating stations or power houses where stored in various forms (examples: water at height, heat energy in coal or oil or nuclear energy in the atoms of fissionable fuels) are converted into electrical energy.

Components of Power System contd.

Transmission system transmits electrical energy in bulk, generally from generating stations to the primary substations.

Distribution system is the system from which electrical energy is distributed to various consumers such as domestic, commercial, industrial, non commercial etc.

NEA Transmission System

Grid (INPS) extends from east to west, ie., Anarmani- Mahendranagar

Major hydro stations connected to the grid. GSS Capacity: 1310 MVA 132 kV line length: 2076 cct Km 66 kV line length: 586 cct Km

NEA Transmission System contd.

Principal voltage of grid system is 132 kV. Majority of the lines constructed with

double circuit, except for Bardghat-Hetauda section

Constructed with conductor BEAR and DUCK except for Bardghat-Hetauda and Bharatpur-Pokhara

Single Line Diagram of INPS

Single Line diagram, INPSI

Lamosangu

Trishuli

AnarmaniM/ nagar

KGA

Modi

Butwal

MMRS

BhrtprHtd

Parwanipur India

Chapur Dhalke

Dubi

Lahan

Jhim

Lamai

Birgunj

Tanakpur

Integrated Nepal Power System (INPS) Map

(NOT TO SCALE)

Why Transmission System Expansion ?

To provide greater reliability and capacity To increase the ability to distribute

available power to meet existing and future demands

To meet NEA’s contractual obligation for transmission with various power producers

To increase NEA’s ability to import/export power

Transmission Development Before 1985: No systematic planning carried out. Transmission expansion mainly by ED, tandem of new

HEP. Major transmission Projects (about 800 km)

Trishuli – Balaju – Hetauda – Birgunj Sunkoshi – Patan Gandak – Bharatpur – Hetauda Devighat – Chabel Bardghat – Butwal - Kohalpur Hetauda – Dhalkebar Bharatpur – Pokhara Suichatar – KL2 - Hetauda

Transmission Development contd. Period Between 1985 - 1992 Transmission network planning started in 80s. NEA Act implemented for effective monopoly NEA Prepared and updated its corporate plan

Long term demand forecasting

LCGEP TSMP Distr. Plan

Transmission Development, 85-92 NEA LCGEP, TSMP & DEP treated as

national plans. NEA responsible for phased

implementation Grid interconnection domestic or interdepartmental affair.

Major Transmission Projects during the period (approx.500km) :

Dhalkebar – Duhabi – Anarmani Kohalpur – Mahendranagar Balaju – Marshyangdi - Bharatpur

Transmission Development after 1992 Period after 1992: New Electricity Act; Hydropower Development

Policy IPPs have access to generation; NEA the grid owner and IPPs the grid user for

existing grid. Absence of national Grid code led many issues

related to grid planning, expansion, operation, interconnection to remain as grey areas.

Grid Interconnection no more interdepartmental issue

Transmission Development after 1992

NEA faced four problems: What level of generation development to be

considered/planned for transmission expansion? IPPs have license throughout country.

Which expansion to be given priority? What performance standards to be adopted for

expansion planning? Source of funding. Where does the money will

come from for transmission expansion?

Mismatched Triangle NEA, IPPs and Government bodies

IPPs

Roles / responsibilitiesAs per Electricity Act

Single buyer marketMissing

Roles ResponsibilitiesFunctionalities Structures

NEA

Roles and Responsibilities as per NEA Act

Monopoly operation

Forced to single buyer

Government bodiesMOWRWECSDOED

Transmission Development after 1992

IPPs are awarded license wherever they apply for and wish to develop power projects where they have license for.

IPPs expect NEA to provide evacuation/ interconnection where they want.

Their proposals for power evacuation include: either to break the existing trunk lines for

interconnection or new transmission line to be constructed by

NEA.

Transmission Development after 1992

NEA refuses: interconnection that harm grid security to add transmission capacity due to lack of

funds. Rigid stands taken by both NEA & IPPs helped to

create bottlenecks or congestion. Ultimately very little transmission expansion

realized. Such expansions include (approx. 345 km):

Transmission Development after 1992

Khimti – Lamosangu – Bhaktapur ( NEA) Lekhnath – Kaligandaki – Butwal (NEA) Chilime – Trisuli (NEA) Pathlaiya – Parwanipur (NEA) Bhotekoshi – Lamosangu (Private) Indrawati – Paanchkhal (Private) Jhimruk – Lamahi (Private)

Current Situation

The conflicting interests created transmission bottlenecks.

Transmission congestion in many sections of the INPS.

NEA transmission plan focuses on meeting its internal demand and limited export.

The TSMP envisages a 220 kV backbone for the purpose.

INPSWestern Area

M/ nagar

KGA

Modi

Butwal

MMRS

BhrtprHtd

Jhim

Lamai

Tanakpur

Pokh

Lekh

Damau

KawasotiBard

MRS

INPSCentral and East

Lamosangu

Trishuli

Anarmani

Htd

Parwanipur India

Chapur Dhalke

Dubi

Lahan

Birgunj

Bharatpur

MRS

Transmission Line Reinforcement Plan

S. No. Transmission lines Proposed year Status

1 Birgunj Corridor 132 kV 2006/07 abandoned

2 Butwal Sunauli 132 kV 2007/08 abandoned

3Thankot-Chapagaon-Bhaktapur 132 kV

2007/08 Under const.

4 Khimti Dhalkebar 220 kV 2007/08 Under const.

5

Kohalpur-Lamahi-Shivpur-Butwal and Khimti Dhalkebar second circuit stringing 2007/08 Planned

6 Hetauda-Bardghat 220 kV 2009/10Under const. (Het-

Bharatpur)

7 Bardghat-Butwal 220 kV 2011/12 Planned

8 Hetauda-Thankot 220 kV 2011/12 Planned

9Bharatpur-Hetauda 220 kV second circuit stringing

2011/12 Planned

Transmission Lines Planned/Proposed for Power Evacuation

S. No. Transmission lines Proposed year Status

1 MiddleMarsyangdi-Marsyangdi 132 kV 2006/07 Completed

2 Kul III-Hetauda 132 kV 2008/09 abandoned

3 Upper Modi-Modi Khola 132 kV 2009/10 Planned

4 Madi I-Lekhnath 132 kV 2009/10 Planned

5 Chamelia-Ataria 132 kV 2010/11 Planned

6 Mewa -Tamor 132 kV 2010/11 Planned

7 Hewa-Kabeli 132 kV 2010/11 Planned

8 Lower Modi-Modi 132 kV 2010/11 Planned

9 Sanjen-Chilime 132 kV 2010/11 Planned

10 Upper Mars-Middle Mars 132 kV 2011/12 Planned

Transmission Lines Planned/Proposed for Power Evacuation contd.

S. No. Transmission lines Proposed year Status

11 Kabeli-Duhabi 132 kV 2011/12 Planned

12 Upper Tamakosi-Khimti 220 kV 2012/13 Planned

13 Tamor-Kabeli 132 kV 2013/14 Planned

14 Kankai-Duhabi 132 kV 2013/14 Planned

15 Upper Karnali-Kohalpur 132 kV 2013/14 Planned

16 Upper Seti-Bharatpur 220 kV 2013/14 Planned

17 West Seti-Ataria 132 kV 2014/15 Planned

18 Likhu-Khimti 132 kV 2017/18 Planned

19 Rahughat-Pokhara 132 kV 2017/18 Planned

20 Dudh Kosi-Dhalkebar 220 kV 2018/19 Planned

21 Andhi khola-Butwal 132 kV 2020/21 Planned

22 Lamosanghu-Singati 132 kV T/L Planned

Planning Dilemma For what capacity to plan the transmission

network? Who can expand transmission when nobody knows what is required? For 83000 MW / 42000 MW? Or for 3200 MW for 2025/26?

Planning horizon? Operational planning of one year. Medium term 1 to 5 years Long term more than 5 years

Where does the money come from if NEA is to satisfy IPPs’ demand?

Over investment: low network utilization

Planning Dilemma contd.

Under investment: limit the use of renewable, increase congestion

A transmission system should have ample margin to allow for contingencies and should deal with the uncertainties of long range forecasts.

A properly designed transmission system provides a good distribution of power flows by avoiding excessive geographic concentrations of generating sources or transmission paths.

Planning Dilemma contd. Performance standards provide the basis for

determining whether system response to the contingency tests is acceptable. What limits/ values to be adopted for these performance standards: thermal, voltage, relay, stability and short circuit.

The maintenance is another issue. An economic network or maintain economy in the life cycle.

What contingency levels to be followed? N-1, N-2 or N-3?

Planning Dilemma contd. Multiple contingency events include the loss of: A tower-line with three or more circuits All transmission lines on a common right-of-way Any transmission station including associated

generation All generating units at a power plant A transmission line or transformer when another

transmission line or transformer is out of service

Development Options and Issues

Generation and Transmission expansion case of chicken or egg story.

For unhindered development of transmission network, Develop networks on the basis of investment, ownership and purpose : INPS owned by Central Transmission Utility (CTU) Commercial or merchant lines of private companies Cross border lines connected to INPS Dedicated cross border lines

Development Options and Issues

Issue is who will, when and how plan expansion, approve, implement and own it and operate transmission systems concerning above models.

Investment for speedy growth is another issue. Government should invest in transmission. Economic feasibility instead of financial feasibility

Development Options and Issues Shall we have a Central Transmission Utility (CTU)? If we have a CTU then shall we have more than one

domestic transmission operators? How shall we attract private investment in transmission? How to fix wheeling charges: MW Miles, capacity

booked or postage stamp Shall we issue transmission licenses anywhere,

everywhere like generation licenses?

Development Options and Issues For what capacity shall we develop our network :

Shall we have separate domestic and export networks? Or allow domestic network for sole export plants?

What will be interface of domestic and export network, AC Synchronous or HVDC back to back?

How shall we export internal surplus through domestic network?

NEA as net integrator and nodal agency? Generators themselves? (Use of CTU network) Trading companies (Use of CTU network)

Transmission System for Future Plan for a long horizon. North South River basin plans:

Kosi Basin Gandak basin Karnali-Mahakali Basin

Southern East West Trunk Line Mid Hill East West Trunk Line Export System

Overall INPS Scheme (Courtesy: S.S. Bhat)

Modi Damauli

Lamki

Butwal

Kathmandu Khimti

Dhalkebar

DuhabiHetaudaBharatpur

Trishuli

Basin Transmission Plan (Courtesy: S.S. Bhat)

90~120 km

MPP to Trunk Line : 30~40 kmSPP to SPP or MPP: 30~60 kmMini PP to Mini PP or SPP or MPP : 20~30 kmWe are pulling North South lines for each P/S

Mini Pooling PointSub Pooling Point

Main Pooling Point

Mid hill trunkline

SouthernTrunk line

Thank You