Transmission Expansion Planning in Deregulated Power ... - tuprints

4 Market Based Criteria 38

k µ lmp is equal to:

1

Nb

k

k

µ lmp = ∑ µ lmp

(4.9)

N i

b i=

1

k

Standard deviation of mean of LMP **in** the presence of plan k ( σ ) **in**dicates how spread

µ

k

out the mean of LMP of different buses ( µ for i=1, 2,…, Nb) are from the average LMP

lmp

of the network ( µ ). As the standard deviation of mean of LMP decreases, differences

k

lmp

among the mean of LMP of different buses decrease and the price profile become flatter.

Flatter price profile **in**dicates less price discrim**in**ation. Accord**in**g to (4.2) as flatness of price

profile **in**creases, congestion cost decreases. Therefore, as the standard deviation of mean of

LMP decreases, both transmission constra**in**ts and price discrim**in**ation decrease and hence

competition is encouraged. In the same way as the standard deviation of mean of LMP

**in**creases, competition is discouraged. Therefore, standard deviation of mean of LMP is a

proper criterion for measur**in**g the competitiveness degree of electric markets.

S**in**ce the budget of transmission expansion is limited, it is logical to provide a competitive

field for more participants or for more power with a given budget. Hence, weighted standard

deviation of mean of LMP is proposed for rank**in**g the transmission plans:

σ µ

with:

k

lmp ,

=

w

k

lmp w , µ

1

Nb

∑ Nb −1

i=

1

w

µ

µ

k k k

i ( lmp −

i

lmp

)

2

i

lmp

(4.10)

σ weighted standard deviation of mean of LMP with the weight w **in** the

presence of plan k **in** $/MWhr

k

w i weight of bus i after add**in**g plan k

Generation power, load, and sum of generation power and load are suggested to weight each

bus.

4.2.2.2 Weight**in**g with Mean of Generation **Power**

The mean of generation power at bus i after add**in**g plan k **in** the peak load of plann**in**g

horizon is given by: