Energy and Power Engineering, 2013, 5, 612-615
doi:10.4236/epe.2013.54B118 Published Online July 2013 (
Research of Security Constrained Dispatching for
Monthly Generation Plan
Rui Ge1, Hai-chao Wang2, Dun-nan Liu3
1Dispatching Control Center, State Grid Corporation of China, Beijing, China
2Dispatching Control Center, Anhui Electric Power Company, Hefei, China
3School of Economics and Management, North China Electric Power University
Received January, 2013
The dispatching for monthly generation plan is to manage the congestion considering the security constrains of the
power grid, where the monthly generation plan is the result of vary monthly power exchange, including long-term pow-
er contract, power exchange among provinces and generation constitu tion exchanges. The applicatio n of monthly secu-
rity constrained dispatching is with significant meaning for the security and stability of power grid. This paper brings
forward the purpose and contents of security dispatching and introduces the working procedure and mathematic models.
At last, the practical example of the Anhui Province power grid is introduced to explain the models.
Keywords: Direct Purchase by Major Users; Security Constrained Dispatching; Monthly Generation Plan
1. Introduction
The medium and long-term contract transaction safe
examination and the blocking management are mainly
examine the electric transmission cross section transmit-
ting capacity and satisfy the tendering space safely the
load demand [1-3 ]. The Anhui Province accent must plan
considered that power plant power capacity, peak load
ability, the electrical network safe operation, the net
woven net damages and so on factors, decided that the
substitution electricity generation trades whether to be-
come effective, and is responsible for the substitution
electricity generation transaction arrangement imple-
mentation which will become effective. The monthly
security examination is the indicator to the electric quan-
tity plan security constraint adjustment, its major func-
tion is examines and adjusts the month electric quantity
plan, causes it to satisfy the regional security constraint
condition, here month electric quantity including de-
composes to the month yearly contract, outside the power
transmission contract as well as the substitution electric-
ity generation tendering electric quantity. The medium
and long-term safe examination’s implementation revo-
lution regarding guaranteed that the electrical network
safe operation, enhances the electric quantity plan the
perform ability to have the important meaning [4, 5].
The needle return ing to p arents’ ho me electric qu an tity
time span is big, the uncertainty strong characteristic, this
article unifies Anhui electrical network characteristic,
proposed that the electrical network monthly electrical
energy plan safe examination’s content and the work
flow, use the tie line race the average stable quota to take
the regional security constraint condition to carry on the
examination computation, and carries on the confirma-
tion by the actual electrical network data.
2. Monthly E l e c t r i city Generation Plan Safe
Examination Goal and Localization
2.1. Current Buys Sells the Electricity
Transaction Pattern and the Market Me-
As shown in Figure 1, current Anhui Province Electric-
ity company monthly transaction including the following
several kinds:
As seen in Figure 1, in buys in straight the electricity
transaction take the province as the unit, has the follow-
ing market main body:
Figure 1. The big user buys the electricity transaction con-
dition straight.
Copyright © 2013 SciRes. EPE
R. GE ET AL. 613
1) The provincial power grid company
Responsibility with not to participation to this prov-
ince buys the electricity the electricity generation com-
pany to sign the order electricity contract straight, buys
with other provinces electrical network sign both sides
sells the electricity contract, and guaranteed that electri-
cal network’s dispatch and the electric power are bal-
2) Participate in direct purchase of electricity genera-
tion companies
Direct purchase of electricity by large users’ platform,
users with large purchase contract entered into directly;
direct power reduction of big users of electricity trade
surplus space, with grid electricity sales contract signed.
Current will participate in the big user buying the
electricity the electricity generation company is straight
in 2004 and the later new production, conforms to the
national capital construction examination procedure and
obtains the electricity generation service permit the
thermoelectricity generation enterp rise (including nu clear
power) and the hydraulic electro generating enterprise.
Among them, the thermal power companies as stand-
alone capacity of 300,000 kw and above business, hy-
droelectric companies for stand-alone capacity of 10 ki-
lowatts or more businesses.
3) Other provinces and Power Company
Power trading with other provinces and cities mainly
bilateral purchase and sale of electricity trading;
4) The province did not participate in direct purchase
of electricity generation companies and signed the grid
electricity sales contract.
5) Large users
The large user may act according to own electric pow-
er demand, the complete demand or a part, buys the elec-
tricity platform and the electricity generation company
straight through the big user signs buys the electricity
contract directly, the surplus demand may also purchase
to the electrical network company.
2.2. Monthly Electrical Energy Transaction Type
Whatever Key Performance Indices are selected, they
must reflect the goals of the business, they must be key
to its success, and they must b e quan tifiab le (measurable).
Key Performance Indices usually are long-term consid-
erations. The definition of what they are and how they
are measured do not change often. The goals for a par-
ticular Key Performance Indicator may change as the busi-
ness goals change, or as it get closer to achieving a goal.
Impact of various ty pes of monthly energy fairs m onthly
power plant planning, in which different transaction price
of the contract, scheduling rights and other regulations
also affect the monthly security correction.
For satisfying outside power transmission contract,
transaction with power plant between; The province in-
side and outside power transmission tender the market
transaction; Saves outside power transmission bilateral
contract between the net and the power plant; Substitu-
tion electricity generation transaction between power
plant; Power plant increase electricity generation con-
2.3. Monthly Security Examination Goal and
With the electricity trading institution s have been built at
all levels, the monthly consumption of electricity market
trading as the main form of the transaction. Scheduling is
based on monthly domestic electricity power plants are
given the full month of the total electricity generation.
However, how does the electric quantity plan carries on
the electrical network to examine safely, the direct rela-
tion monthly plan execution’s feasibility, becomes the
question which urgen tly awaits to be solved. The present
solution is: The electric quantity examination way,
soon electrical network’s electric power restraint conver-
sion for the monthly electric quantity restraint, this way
serious influence power plant entire month power rate;
The electric power examination way, decomposes the
various power plants’ monthly electric quantity into the
electric power plan, then carries on the safe examination,
but the electric quantity decomposition principle deter-
mined with difficulty.
2.4. Security Check on the Contents of Anhui
According to Anhui Province’s actual situation, this re-
port proposed that Anhui electrical network monthly se-
curity examination’s pattern is as follows:
1) The examination object -- power plant monthly
buys the electricity plan straight
Anhui monthly security check of the calibration grid
target is based on the types of transactions monthly pow-
er generation projects, including the province transac-
tions: decomposition of the annual contract to replace the
contract; province of: tie-line planning, delivery power
New power plant signed monthly direct power schemes
need confirmation through security check and adjust the
order of security checking transactions by direct power to
declare the order of execution.
2) Examination content -- four safe examinations
Anhui electrical network monthly security examina-
tion will carry on the following four examinations to
various power plants’ electricity generation plan:
Monthly total electric quantity examination: Forecast
according to the monthly electricity consumption that
carries on the safe examination to various power plants
Copyright © 2013 SciRes. EPE
monthly plan electric quantity, and carries on the safe
adjustment according to the check result.
On way to check the maximum: the maximum load
forecast based on month, the maximum load on the out-
put mode of the plant for security check;
Month master curve: Forecast according to the month
typical date 96 spot loads that carries on the decomposi-
tion to the power plant monthly electricity generation
contract, and considered that the unit overhauls, situa-
tions and so on line overhau l, carries on day after day 96
model load diagram.
3) Anhui electrical network dist rict analysis si tes model
We can introduce the conception of KPI to the analysis
of electricity market, which is one of the most important
tasks of market surveillance committee.
According to the electrical network district analysis
sites model's construction thought that may carry on the
safe area division to Anhui electrical network, and estab-
lishes the corresponding computation model. According
to Anhui electrical network's geographic distribution
characteristic and the safe stable regulations, Anhui elec-
trical network may divide into A, B, C, D, E, F, G, H, I
altogether 9 security district, in each security district
contains the ration the power set and the system load, its
analysis sites connection relations see also Figure 2:
When concrete division safe area, needs to solve the
following problem:
a) Various power plants and safe area subordination
b) Each main load and safe area subordination rela-
c) Various transformer substations and safe area sub-
ordination relatio ns.
When divides the security cross section, needs to solve
the following problem:
According to the above safe area actual model, may
carry on the simplification, obtains analysis situs model
which the electrical network calculates, like Figure 2:
a) To connect the different safe area the tie line race
forms the security cross section;
b) Determines between various tie lines and the cross
section subordination relations.
4) Safe examination step and algorithm
Anhui electrical network monthly security examina-
tion may divide into the following four main steps:
a) District load forecast
The district load forecast is responsible to act accord-
ing to the monthly safe area the division, forecasts vari-
ous safe areas separately the electricity consumption or
the load, including the following four targets:
Various safe areas monthly electricity consumption;
Various safe areas monthly valley even three time in-
terval electricity consumption;
Various safe areas month biggest load;
Figure 2. Anhui electrical network safe examination com-
puting network model.
Various safe areas which month typical date 96 load
b) The electricity generation plans the pre-decomposi-
tion strategy
According to the total electric quantity examination,
three time interval electric quantity examination, the
biggest load examination and 96 typical date curve ex-
amination’s request, the power plant monthly plan carries
on the decomposition to the province, satisfies the safe
examination the need.
c) District cross section safe examination algorithm
There are two typical indices to explain the risk of ge-
nerators’ bidding str at e gy.
According to the safe area division, to between various
safe areas’ tie line race, forms the security cross section.
The distinction computation each security cross section
may transmit capacity ATC; Decompose according to the
district load forecast and various power plants plan, carry
on the district electric power balance computation, ac-
cording to the computed result, verifies each security
cross section one by one actual transmission electric
quantity and may transmit the capacity.
d) Multi-criterion safe adjustment
To surpasses the cross section to be possible to trans-
mit the capacity situation, should the overall evaluation
electrical network security goal, the economic target, the
energy conservation goal, the contract progress goal and
so on carry on the multi-objectives the overall evalua-
tions, makes the optimized adjustment to the related dis-
trict electricity generation plan, completes the safe ad-
justment. Like Figure 3:
3. Example Analysis
Below take Anhui electrical network some safe area as
Copyright © 2013 SciRes. EPE
Copyright © 2013 SciRes. EPE
Table 2. After the adjustment, a area electrical network
electric quantity balanced plan.
an example, carries on the synthesis confirmation to the
monthly electricity generation plan safe examination
algorithm, and gives the monthly electricity generation
plan safe examination the adjustment effect. According
to the safe area which and the tie line race assigns define,
follow the district adjustment the thought that before
having given the adjustment, this safe area electric quan-
tity balanced plan, see Table 1.
rate Total
load Tie line race 1
upper limit Tie line race 2
upper limit Tie line race 3
upper limit
20.1511.362.45 3.11 3.23
Looking from the electrical network actual operational
aspect, after the revision electric quantity plan has the
strong feasibility, has safeguarded electrical network's
security reliability service, have received the movement
personnel’s co nsi st ent hi g h prai se.
Through to the power rate, always shoulders, the tie
line race tidal current upper limit to carry on the electric
quantity balanced to be possible to know that a area pri-
mitive electric quantity transaction plans excessively
high, the monthly power rate plan is bigger than always
shoulders transmits the upp er limit sum total with various
tie lines race: 4. Conclusions
This article links to the provincial level electrical net-
work reality, proposed the monthly electrical energy plan
safe examination work’s content, the duty and the ex-
amination method, lay th e rationale for Our country Pro-
vincial level Electrical network Company monthly secu-
rity examination work’s development. Anhui electrical
network’s application example indicated that this article
proposed the algorithm can propose the important crite-
rion for the pre-electric quantity transaction plan, re-
garding maintenance substitution electricity generation
electric power market public, fair, fair principle, guaran-
teed that the electrical network safe operation has the
important meaning.
20.67 > 11.36 + 2.45 + 3.11 + 3.23 = 20.15
The actual execution had certain difficulty, after Table
2 has given the adjustment a area electric quantity bal-
anced plan.
This adjustment scheme scaled down in this safe area
the power plant power rate. In guaranteed that under entire
net power supply total quantity certain premise, changes
by other safe area increases the electricity generation
[1] H. C. Shi and H. S. Liu, “Application of Secure Active
Power Real-Time Dispatching In AGC In Yunnan Power
Grid,” Water Resources and Power, Vol. 27, No. 4, 2009,
pp. 212-214.
[2] L. L. Li, J. Geng, J. G. Yao and Z. L. Yang, “Model and
Algorithm for Security Constrained Economical Dispatch
in Equilibrium Power Generation Dispatching Mode
Source,” Dianli Xitong Zidonghua/Automation of Electric
Power Systems, Vol. 34, No. 15, 2010, pp. 23-27.
[3] D. N. Liu, R. Q. Li, X. Q. Chen, et al., “Surveillance
Indices and Evaluating System of Electricity Market,”
Automation of Electric Power Systems, Vol. 28, No. 9,
2004, pp. 16-21.
[4] D. N. Liu, X. Q. Chen, G. Y. He, et al., “Analysis and
Coutermeasure for Suppliers’ Behaviors in Electricity
Market,” Automation of Electric Power Systems, Vol. 29,
No. 6, 2005, pp. 24-28.
Figure 3. Anhui electrical network monthly security ex-
amination flow. [5] Z. X. Chen, K. Xie, J. Zhang, Z. L. Yang, J. Liu and H.
Wang, “Optimal Model and Algorithm for Day-ahead
Generation Scheduling of Transmission Grid Security
Constrained Convention Dispatch,” Dianli Xitong Zi-
donghua/Automation of Electric Power Systems, Vol. 33,
No. 1, 2009, pp. 10-13.
Table 1. Before the adjustment, safe area electrical network
electric quantity balance d plan.
rate Total
load Tie line race 1
upper limit Tie line race 2
upper limit Tie line race 3
upper limit
20.67 11.36 2.45 3.11 3.23