Research On Control Standard Of Tie-line Overload

In order to reduce the environmental pollution of fossil energy electricity generation,in the future,the proportion of clean and renewable energy like solar and wind in power generation will increase gradually.For more reasonable and efficient use of clean energy,our country is vigorously constructing UHV grid interconnection.Because of electricity load center is far away from energy concentration distribution areas geographically in China,power must be transmissed by high voltage transmission lines cross-regionally,to achieve cross-regional accommodation of the clean energy.The transport space of tie-lines between regionals is necessary to be let go as far as possible,to undertake the task of large-scale,long-distance power transmission better.In the meanwhile,it will make the tie-lines transmission power has a higher chance of overlaod.The UHV transmission capacity of tie-line is huge,in the event of power overload,it will bring very serious impact to the safe and stable operation of the power grid.In order to avoid system safety fault caused by tie-lines overload,it is necessary to have an effective way to restrict flow on tie-lines.So as to achieve that under the premise that guarantee for safe operation of the tie-line,make the most of its transmission capacity.In the operation of the power system management,by making a series of all kinds of standards to ensure safe and stable operation of the system.Because of the existing tie-line related control standards all have certain limitation,it is necessary to design a tie-line control evaluation standard which is satisfied with the current situation of the development of UHV power grid in our country,suitable for scheduling environment,involving the specific control indicators,able to ensure the safety of tie-line operation.In view of the above requirements,this paper designs the tie-line overload control standards in our country.Based on comprehensive analysis of wide-area regulation and control in our country given the current situation of the development of renewable energy power grid,and deeply analysis of the existing standards,it is cleared about the designing idea,the purpose of performing,and the object of the constraints of this standard.The settings of the limit and the weight of the limit of liability are solved.The appraisal of the standard is determined,and analyzes the possible case while the tie-line overload in the appraisal time and sets starting time of the standard in different circumstances.Designing the formula and requirement of the responsibility degree of control areas.The concept and calculating method of the sensitivity from the change of ACE in control area to the power fluctuation of tie-lines are proposed,the sensitivity is an important parameter in the standard.The calculation formula of the responsible power of each control area takes while tie-lines overlaod is designed.The responsible power and the responsibility degree can collectively be the basis to evaluate the influence of the regulating behavior of areas while tie-lines overload.Based on the Matlab Simulink,the sensitivity from the change of ACE in control area to the power fluctuation of tie-lines in IEEE 39 nodes system is calculated,the correctness and rationality of the standard which proposed by this paper are verified.