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generation refers to trading tools to promote the substitu-
tion of low-capacity and high-energy generating units for
generating units with high capacity and high energy effi-
ciency, to achieve energy saving and emission reduction
through the market-oriented means. The main transaction
process is as follows:
1) Electricity Trading Center releases the centralized
transaction reporting notification about monthly alterna-
tive power on 16th of each month, and clarifies trading
days.
2) Before 17:00 in the first 2 working days of trading
days, the power Trading Center releases the next month's
monthly pre-power projects of trading unit, and trading
unit involved in alternative power generation focused on
transactions monthly maximum transfer/transferee power
of monthly alternative power centralized transaction.
3) Trading subjects participating in the centralized
transactions of monthly alternative power generation
confirm the transferors/transferees’ status through tech-
nical support systems of alternative power generation
transactions to the power grid electricity trading center in
Hunan, and submit the transaction declarations from
9:00pm in the trading day; 9: 00-12:00 am in the trading
day is a free reporting period; 12:00 in the trading day is
a deadline for reporting, and technical support system
will match the clearing according to the final effective
transaction d eclarat i o n s .
4) The power trading center will hand over the pre-
liminary results of monthly alternative power generation
centralized transaction to Hunan Electric Power Dis-
patching and Communication Center before 17:00 in the
transaction day.
5) Dispatching and Communication Center will com-
plete the safety check of the transaction preliminary re-
sults, and feedback the checking suggestions to the elec-
tricity trading center before 17: 00 in the third working
days after the transaction day.
6) The power trading center will make the necessary
adjustments for the preliminary results of the transaction,
until the security check is passed and the centralized
trading results of monthly alternativ e power generation is
formed. Additionally, the power trading center power
generation releases and issues transaction notice to the
relevant transaction subjects through technical support
systems about alternative power generation trading be-
fore 17:00 in the fourth working day after the trading
days.
7) Dispatch communications center is responsible for
the implementation of centralized trading results of
monthly alternative power generation.
3. The Main Process of Security Checking
According to the orders about security and stability
and existing scheduling and running system, on the basis
of the appropriate partition of the entire power grid and
the formation of multiple independent security zones,
security checking software regards the average stable
limits of the contact line as constraints to test and adjust
the monthly power plan, so as to meet the needs of secu-
rity and stability of inter-regional power transmission.
Figure 1 shows the basic model o f the middle-long term
safety checking, the power grid by consists of two safety
zones labeled by A and B, contact line is denoted with T.
According to the power balance relationship after
safety partition of A zone, the flow of contact line T can
be calculated by the following fo rmula:
AA
T1,1 1
g
tl
N
NN
tg
tgl
WW WW
A
l
(1)
where
W denotes the monthly planning power of unit
g; t dentes the flow of contact line t; l
W denotes
load capacity of the month;
W
N represents the total
number of units; t represents the number of contact
lines, represen ts the number of load nodes.
N
l
Similarly, the following formula can be obtained from
the power balance of zone B:
N
BB
Tt
111
g
tl
N
NN
l
tlg
WWWW
B
g
T
B
(2)
with the consideration of the upper and lower space of
generation output of each partition, and the flow con-
straints of contact line groups, the amount of planning
power adjustments can be expressed in the following
formula:
,maxA B,max
,minA B,min
min{(),,} ,
dmin{ (),,},
TTT T
A
TT T
WWSS WW
WWWSSWW
(3)
A
ddWW (4)
where is the adjusting amount of planning power
of zone A; is the amount of power adjustments;
T is the flow of contact line groups; ,maxT
W is the
upper flow limits multiplied by upper stable limits of
contact line groups, the average load rate and adequacy
factors; ,minT is the lower flow limits multiplied by
lower stable limits of contact line groups, the average
load rate and adequacy factors; the up-regulated space of
security zone A
A
dWd
W
B
W
S
W
, B
S
refers to the increased power
with the biggest possibility of generation plants within
Figure 1. The basic model of the middle-long term safety
checking.
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