Transcript P. Kuale and J. Ekeh

Third NSF Workshop on US-Africa
Research and Education Collaboration
Abuja, Nigeria, December 13-15, 2004
TECHNOLOGY &
ENVIRONMENT
ENERGY &
EDUCATION
Application of Locational Marginal Pricing for
Transmission Congestion Management in the
Proposed Power Industry Reform in Nigeria
P. A. Kuale and J. Tsado
University of Benin, Benin City
J. C. Ekeh
Ambrose Alli University, Ekpoma
Outline
1. Objectives
2. Existing Market Structure
3. Proposed Nigerian Power Industry
Reform
4. Consequences of Reform
5. Review of Loadflow Studies
6. Findings
Kuale/Ekeh
Third US-Africa Research and Education
Collaboration Workshop
Abuja, Nigeria, December 13-15, 2004
2
Outline
7.
8.
9.
Concepts of Locational Marginal Pricing
(LMP) and its Impact on the Proposed
Electricity Reform
Applications
Conclusions and Future Work
Kuale/Ekeh
Third US-Africa Research and Education
Collaboration Workshop
Abuja, Nigeria, December 13-15, 2004
3
Objectives
• Review of the state-of-the-art of the
loadflow studies of the transmission lines
under existing and proposed IPPs
• Identification of critical nodes/buses
• Define LMP and it can be used to check
transmission congestion
Kuale/Ekeh
Third US-Africa Research and Education
Collaboration Workshop
Abuja, Nigeria, December 13-15, 2004
4
Consequences of Reform
1. Increase of reliability of power supply
2. Overall increase in power consumption
3. Increase in competition among generating
plants
4. The results of (2) and (3) could result in
congestion
5. The consequence of (4) could result in
different energy prices throughout the network
6. Adoption of appropriate pricing policies to
check transmission congestions
Kuale/Ekeh
Third US-Africa Research and Education
Collaboration Workshop
Abuja, Nigeria, December 13-15, 2004
5
Congestion Management
• Reschedule system generation
• The use of locational marginal pricing
• Other methods: postage-stamp rate,
contract path, MW-mile, ATC, etc
Kuale/Ekeh
Third US-Africa Research and Education
Collaboration Workshop
Abuja, Nigeria, December 13-15, 2004
6
Findings
• Shiroro-Kaduna line was overloaded by
18.65%
• Ajaokuta busbar exceeds max acceptable
voltage of 1.05 pu – the bus voltage was
1.062 pu
• Shiroro and Afam GS exceeded their Var
limits – the values were 2.60 and 1.59 pu,
respectively
Kuale/Ekeh
Third US-Africa Research and Education
Collaboration Workshop
Abuja, Nigeria, December 13-15, 2004
7
Findings
• Jebba GS and Delta GS absorb min Var of
-2.0 pu and -2.49 pu, respectively
• Kaduna (0.9025 pu), Kano (0.8268 pu),
Jos (0.7858 pu), and Gombe (0.6397 pu)
all recorded low voltages
• There is the need for appropriate pricing
mechanism for transmission congestion
management
Kuale/Ekeh
Third US-Africa Research and Education
Collaboration Workshop
Abuja, Nigeria, December 13-15, 2004
8
Locational Marginal Pricing
•
•
•
The LMP is the spot price which is based on the
principle that a unit of power has different prices at
different points in the network. The main reason for this
spatial discrimination in energy prices are transmission
losses and congestion
LMP is defined as the minimum cost of supplying one
additional MW of load as the load bus without violation
of any transmission limits, based on the bidding prices of
power supply and power load at the buses in the system
The major factors affecting the LMP values are
generator bid prices, transmission system elements that
are experiencing congestions, the losses in the system,
and the electrical characteristics of the system
Kuale/Ekeh
Third US-Africa Research and Education
Collaboration Workshop
Abuja, Nigeria, December 13-15, 2004
9
Locational Marginal Pricing
•
Usefulness of LMP
1. To calculate the revenue of GENCOs for supplying
electric power and the expenditure of DISCOs for
using electric power
2. It can be used for the transmission congestion
management
3. It can be used for transmission network planning to
improve the secure operation network of the power
system
4. To guide TRANSCOs’ capital investments
Kuale/Ekeh
Third US-Africa Research and Education
Collaboration Workshop
Abuja, Nigeria, December 13-15, 2004
10
Applications of LMP
• At the Shiroro GS busbar/node – this will
take care of the Shiroro-Kaduna line,
Kaduna-Kano line, Kaduna-Jos line, and
Jos-Gombe line
• At the Ajaokuta load bus because of the
max acceptable voltage of 1.05 pu was
exceeded.
Kuale/Ekeh
Third US-Africa Research and Education
Collaboration Workshop
Abuja, Nigeria, December 13-15, 2004
11
Conclusions and Future Work
•
•
•
The existing system is weak to cope with
the proposed electric power reform
LMP will help to alleviate transmission
congestions
The above will save the grid from high
losses, occasional trippings, voltage as
well as system instability
Kuale/Ekeh
Third US-Africa Research and Education
Collaboration Workshop
Abuja, Nigeria, December 13-15, 2004
12