Algorithm Research And Software Development On Automatic Calculation Of Large-scal Interconnected Power System's Total Transfer Capability

When calculating transient stability constrained total transfer capability, power dispatching departments generally adjust load flow and perform a couple of stability simulations for different contingencies continuously by use of power system analysis software, and judge whether the system is stable according to time-domain simulation curves. This process would take too much manpower and time because it requires repeated adjusting load flow manually and judging whether the system is stable according to time-domain simulation curves. When calculating transient stability constrained total transfer capability for poor convergence network, it would be difficult to guarantee load flow calculation convergence by adjusting outputs of generators, changing active power or reactive power of load, switching shunt capacitor or shunt reactor, adjusting transformer tap changer although solution of the load flow does exist. It would increase the work load of system analysis staffs further. To address the above problems, the main contributions done by this paper include as follows:(1)The convergence of load flow which is adjusted continuously for total transfer capability calculation is studied first. For ill-conditioned network, this paper presents a new algorithm named'ill-conditioned load flow algorithm based on time-domain simulation'. If load flow solution does exist, this algorithm can effectively guarantee load flow calculation convergence.The experimental results of national interconnected power grid data verified the validity of the proposed algorithm.(2)Based on (1), a detailed algorithm design for automatic calculation of large-scale interconnected power system's total transfer capability is presented in this paper.(3)In view of the actual total transfer capability calculation process of electric power dispatching departments, with the proposed algorithm of this paper, a stability constrained total transfer capability calculation tool is developed based on Power System Analysis Software Package (PSASP). The simulation results of 5000 nodes and 15000 nodes illustrate the correctness and validity of the proposed algorithm and practicality of the software tool.(4)Based on PSASP parallel computation platform, a parallel computing framework to calculate total transfer capability is proposed in this paper.