State Estimation of Combined Heat and Power Systems Considering Thermal Dynamics and Different Time-Scale Measurements

Sate estimation is required to obtain sense the operating state accurately. Aiming at the problem of dynamic process of thermal system and measurement scale difference of thermal and power system, a method of state estimation of combined heat and power system (CHPS) is proposed. To solve the problem of the great difference in response time and rate of change between thermal system and power system, the difference equation is introduced to describe the transient process of thermal system. Considering that the two networks have different measurement frequencies, the more accurate measurement data of power system at the CHPS coupling is used to obtain the accurate data in the interval of heating network measurement. The data of the boundary of the thermal system is calculated through the coupling constraint equation in the CHPS, which is used as pseudo-measurement to obtain better state estimation effect. The data obtained by the above methods are fused with the measurement data of the thermal system to improve the data accuracy. It is beneficial to improve the effect of real-time scheduling when introducing the calculation of pipeline storage capacity into consideration, so the pseudo-measurement and dynamic models are used to calculate pipeline storage. Simulation results show that the state estimation accuracy of these methods are better than that of the steady-state model and the traditional pseudo-measurement generation method.