ANNEXURE-II

Formulae for calculation of Availability of each category of transmission elements

                                                                             o                             / 0
AVo(Availability of o no. of AC lines) =           å Wi(Ti -TNAi)  / å Wi
                                                                            i=1       Ti          /    i=1

                                                                                p                      / p
AVp(Availability of p no. of HVDC pole) = å Wj(Tj -TNAj) / å Wj
                                                                                j=1      Tj    /    j=1

                                                                              q                                  / q
AVq(Availability of q no. of ICTs) = å Wk(Tk - TNAk)  /  å Wk
                                                                            K=1         Tk           /    k=1

                                                                          r                                    r
AVr(Availability of r no. of SVCs) = å 0.5WIl (TIl -TNAIl) + å 0.5 WCl (TCl – TNACl)
                                                                          l=1               TI      l      l=1                    TCl

                                                                           -------------------------------------------------------------
                                                                                       r                   r
                                                                                      å 0.5WIl + å 0.5 WCl                                                                                        i =1               l=1

                                                                                                              /    s
AVs(Availability of s no. of Switched    =    å    Wm(Tm-TNAm)    /   å Wm
            Bus reactors)                                                    Tm              /     m=1              
                                                                                                                                                                                     

AVt (Availability of t no. of HVDC = å Wn(Tn-TNAn) /å Wn

Back-to-back Blocks) n =1 Tn n =1
Where Wi = Weightage factor for ith transmission line
Wj = Weightage factor for jth HVDC pole
Wk = Weightage factor for kth ICT
WIl & WCl = Weightage factors for inductive & capacitive operation of lth SVC
Wm = Weightage factor for mth bus reactor
Wn = Weightage factor for nth HVDC back to back block
Ti, Tj, Tk, TIl, TCl, - The total hours of ith AC line, jth HVDC pole, kth ICT, lth SVC (Inductive
Tm & Tn Operation), lth SVC (Capacitive Operation), mth Switched Bus Reactor & nth HVDC back-to-back block during the period under consideration (excluding time period for outages not attributable to POWERGRID for reasons given in Para 6 of the procedure)
TNAi , TNAj , TNAk - The non-availability hours (excluding the time period for outages not
TNAIl, TNACl, TNAm, attributable to POWERGRID taken as deemed availability as per Para 5 of TNAn the procedure) for ith AC line, jth HVDC pole, kth ICT , lth SVC (Inductive Operation), lth SVC (Capacitive Operation), mth Switched Bus Reactor & nth HVDC back-to-back block .