State Estimation of Power System with Interline Power Flow Controller by Academy Publisher

Author:Academy Publisher
Language: eng
Format: epub
Tags: IPFC, Power Injection model, FACTS, State Estimation, WLS.

t=0 t= t=2 1=3

Fig'. 1 Unit on/off status

The dynamic programming part must take into account all the start up costs as well as the minimum up and down time for the generating units.

At U t =0 state the value of function to minimize is

zero. At U j =1 state the function to be minimized is

min[i^. (P' ) - XP. ]. The minimum of this function is found by taking the first derivative

-^— [ F t i p t ) —-HP,' ] =0

(18)

■)t,opt

The dual power ' is obtained from (19) X -b,

pt.opt __

2c ;

(19)

ifP!-" P '<P^ then PI = P imm if P ;** > P t ^, ihenP;=P t ^ (20)

if P < P''" p ' < P , then P' = P*'" p *

J z.min — i — /.max ' t,lt " t ; ;

The dual power obtained from (20) is substituted in on/off decision criterion DC

DC] =[F i {P<) + ST{(\-U<i )-XP; -M'P^l (21)

If DCi < 0 the unit will be committed if it does not

violate minimum downtime constraint, otherwise the unit is decommitted if it does not violate the minimum uptime constraint. A step-by-step procedure for the proposed method is outlined as follows.

Section -A:

Stepi: Compute X and JLl' by Chemo-tactic PSO-DE.

Step2: Set the unit status by calculating dual power and obtain on/off decision DC (21).

Step3: Calculate the spinning reserve for generated 'U' status at each hour of the population. If excessive spinning reserve is observed decommit the unit with high full load average production cost if it does not violate the minimum uptime constraint. Otherwise if the unit violates, the unit with next high full load average production cost is decommitted. Now set the spinning reserve according to the new status and repeat until the spinning reserve satisfies. Step4: If less spinning reserve than required is observed commit the unit with less full load average cost if it does not violate the minimum downtime constraint. Otherwise if it violates, the unit with next less full load average production cost is committed. Now set the spinning reserve according to the new status and repeat until the spinning reserve satisfies. Steps: Economic dispatch for the generated U-status is carried out by Lagrangian multiplier method.

Section-B:

Stepi: Randomly generate X > [1 > VX > an d VjU with in the range for initialized bacterium. Generate unit-status U as in section-A and calculate pbest for U, X , U 1 , cost and fit (J and JF) and gbest for U, X , H l , J and JF.

Step2: Starting of the chemo-tactic loop (ir=it+l) Step3: For each bacteria (k=k+l) JFlast =JF(k)

Step4: Calculate VX, VfX and check for maximum

and minimum velocity limits.

VX(k)=VX(ls)

+ C, * Rand * {pbestZ (k) —Z (k)) (22) + C 2 * Rand * (gbestZ —Z (k))

VjU (k) =VjU (k)

+C, * Rand * (pbestjU (k) —/J (k)) (23) +C 2 * Rand * (gbestjU —/J (£))

Steps: Move to new position

SL(k) =JL(k) +C^ *vA.{k)

jU(.k)=jU{k)^-C M *V/J{k) ( 24 >

where C x and C^ are chemo-tactic step size Step6: Handle limits

• ^ / ^ (25)

53

©2010 ACEEE DOI:01.

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