DC power flow calculation method considering charging capacitance

Abstract

The invention relates to a DC power flow calculation method considering charging capacitance. The DC power flow calculation method comprises steps of (1) calculating a trigonometric function simplification method and an approximation coefficient, (2) constructing a DC power flow model considering a charging capacitance, (3) incorporating a circuit model containing a charging capacitor and a grounding admittance, (4) using a complete admittance matrix parameter to calculate a coefficient matrix, (5) solving voltage amplitudes of all PQ nodes through back substitution of a correction phase angle to obtain voltage amplitudes and phase angles of all nodes in a network and using complex power flow equation to calculate line circuit complex power. Compared with a DC power flow algorithm without considering a charging capacitance, the DC power flow calculation method improves calculation accuracy of the voltage amplitude and the reactive power flow on the premise that the active power flow calculation accuracy of the current DC power flow algorithm is maintained, and enables the power flow algorithm to be adapted to calculation of reactive power flow of a power transmission system.

Description

technical field [0001] The invention relates to a DC power flow calculation method considering charging capacitance, and belongs to the technical field of power system analysis. Background technique [0002] DC power flow is a simplified algorithm for AC power flow calculation. Because of the linear expression and rapidity of its mathematical model, it is widely used in power system day-ahead power generation plan checking, economic dispatch, power market congestion management, and power system cascading failure analysis and many other occasions. Among the existing DC power flow calculation methods, the standard DC power flow algorithm has a good calculation effect for systems with a ratio of x / r close to 4 and a standard deviation of voltage amplitude less than 0.02. However, in practical applications, the system parameters may not meet the above requirements. Requirements, so the calculation accuracy of the algorithm is difficult to guarantee. In order to improve the calc...

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Problems solved by technology

Among the existing DC power flow calculation methods, the standard DC power flow algorithm has a good calculation effect for systems with a ratio of x / r close to 4 and a standard deviation of voltage amplitude less than 0.02. However, in practical applications, the system parameters may not meet the above requirements. Requirements, so the calculation accuracy of the algorithm is difficult to guarantee

In order to improve the calculation accuracy of the DC power flow algorithm, the known AC power flow section can be used to form the correction item or the network loss equivalent load can be obtained through iteration and used to correct the node power. However, the former has the problem of how to select a suitable historical AC power flow section, and the latter The latter has the problem that the voltage amplitude cannot be calculated and iteration is required; in order to solve the problem that the balanced node injection power caused by ignoring the network loss is obviously unreasonable, the resistance is considered in the line model, and the node reactive injection power is considered in the network equation. It can greatly improve the calculation accuracy of DC power flow while considering the characteristics of voltage amplitude fluctuations and network losses, but it is only used to calculate active power and does not further analyze the calculation of reactive power

On the basis of the standard DC power flow algorithm, the reactive power of the line can be directly estimated by using the assumed power factor combined with the active power. It is related to the fixed power factor, which has great randomness, and it is difficult to calculate the accurate reactive power flow

Therefore, there is still a lack of a DC power flow calculation method that can simultaneously take into account the calculation accuracy of active power and reactive power.

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