A steady-state energy flow analysis method for integrated natural gas and power systems based on topology decoupling

The existing analyses of integrated natural gas and power systems generally ignore gas temperature variations, which may misjudge gas pressure and jeopardize natural gas transmission. Furthermore, the conventional Newton-Raphson based natural gas flow analysis methods may cause non-convergence or unnecessary computational burden. Based on topology decoupling, an efficient energy flow analysis method is proposed in the paper for integrated natural gas and power systems with the consideration of temperature distribution in natural gas systems. A lumped parameter model of natural gas flow in pipelines considering temperature is developed based on the Weymouth and Shukhov formulas. A natural gas flow model considering temperature is then established. According to the topological characteristics of natural gas systems, a topology decoupling based natural gas flow analysis method is proposed to improve computational efficiency and to lower the requirement of initialization. An energy flow analysis method for integrated natural gas and power systems is presented based on a NewtonRaphson method. The correctness and adaptability of the proposed method are verified using three widely-used test systems. The obtained simulation results show that the temperature distribution and natural gas pressures of a natural gas network can be accurately described and estimated to ensure the secure operation of integrated natural gas and power systems, and the computational efficiency and convergence performance are largely improved.