Available Transmission Capacity (atc) And The Transient Stability Margin And Sensitivity In The Electricity Market

In electric power market, the transmission capability of branch section is very important for the security and reliability of power system under both the small and large system. It can not only instruct the dispatch of the dispatcher and confirm the stability and security of the system, but also it can be seen as market signal to instruct all kinds of trade actions of market participants. It can be used for fully utilizing the generation resource and decrease the produce cost. So research about the solution of ATC of branch section in electric power market is done in the paper, and the solution of ATC considering transient stability is proposed.In the paper, the transmission power of section constituted by the assigned branch is seen as objective function, assigning the adjustable generators both in sending system and receiving system, assigning the faults set, including the constraint conditions such as the differences between the angles of rotor and the inertia center angel of the whole system, the thermal stability of branch and node voltage, obtaining the results by using interior-point solution and Line-predominant Jordan. Optimization results of 5-node system validate that this method not only greatly quickens the calculation speed, but also has good numerical convergence performance, also indicate that the method proposed in the paper has preferable systematic and scientific performance, wide application prospect and strong theoretical value.There are two kinds of load modeling. One is constant impedance modeling, the other is complicated load modeling. Based on the time domain simulation, the sensitivity of stability margin with respect to node active and reactive power for the system with complicated load modeling is derived. The sensitivity of the state variables of the differential equations under larger disturbance at any time can be obtained by using the method proposed in this paper. When the changes of the disturbance variables are not too great, the first order sensitivity method has good accuracy. The sensitivity of stability margin can be used in the location selection of transient stability control devices, stability margin constraint of security based economic dispatch and online stability monitoring. Practical system analysis is presented.