Probabilistic energy flow analysis method for electricity-gas interconnection system considering thermal process of natural gas system

Abstract

The invention discloses a probabilistic energy flow analysis method for an electric gas interconnection system considering a thermal process of a natural gas system, and the main steps are as follows:1) sampling the electric gas interconnection system. 2) establishing a device model that considers the thermal process of the natural gas system. 3) establishing a probabilistic energy flow model ofthe electrical-air interconnection system. Wherein The probabilistic energy flow model of the electrical-air interconnection system includes a node equilibrium equation and an uncertainty factor model. 4) establishing a risk indicator model. 5) inputting the sample data into the probabilistic energy flow model of the electric gas interconnection system, calculate the energy flow of the electric gas interconnection system, and input the result into the risk indicator model to calculate the risk index of the electric gas interconnection system. 6) making convergence judgment. The invention proposes a comprehensive consideration of various devices existing in the natural gas system, and a probabilistic energy flow calculation and analysis method for the thermal process in each device, which can more accurately and effectively analyze the system state and evaluate the risk situation.

Description

technical field [0001] The invention relates to the field of electric-gas integrated energy systems, in particular to a probabilistic energy flow analysis method for an electric-gas interconnected system considering the thermal process of a natural gas system. Background technique [0002] In recent years, with the increasing installed capacity of gas turbines, the coupling between the power system and the natural gas system has become increasingly close, and it is increasingly common to regard the electricity-gas interconnection system as a unified whole for calculation and analysis. In the electrical-gas interconnected system, there are a lot of uncertain factors, which makes the probabilistic energy flow calculation method known as an effective analysis tool to reflect the over-limit risk of state variables such as voltage and air pressure. [0003] At present, in the unified calculation and analysis of the electrical-gas interconnection system, only natural gas pressure ...

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Problems solved by technology

First of all, the existing literature considers the thermodynamic process of the pipeline and establishes the nodal thermodynamic balance equation, but the contradiction lies in the fact that the Weymouth equation is used as the flow model of the pipeline, but in fact the Weymouth equation is based on the assumption that the temperature of the entire pipeline is constant deduced, so the computational accuracy of using this model in the context of considering thermodynamic processes is limited

Secondly, for the voltage regulator, in the current research on the electrical-pneumatic interconnection system, there are only some literatures that include the upper and lower limits of the pressure regulation ratio as constraints in the optimization calculation, or according to the characteristic of fixed air pressure at one end, the pressure regulator and the compressor are combined. The machine is classified as an active branch, and the detailed modeling of the voltage regulator has not yet been seen

Thirdly, for the compressor, its thermodynamic process will lead to a significant rise in the outlet temperature, and this characteristic has not been effectively considered in the existing electrical-gas interconnection system research

All in all, the existing studies are not comprehensive and detailed enough to consider the natural gas system equipment and its thermal process

[0008] For indicators, the existing research can calculate the node voltage, the probability of exceeding the limit of the gas pressure, and the overload probability of the branch power flow, etc., but there is still a lack of indicators that can quantify the probability of hydrate formation (affected by the two state variables of natural gas temperature and pressure)

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