Resident distribution unit area three phase unbalanced load flow calculating method taking regard of load characteristics

Abstract

The invention discloses a resident distribution unit area three phase unbalanced load flow calculating method taking regard of load characteristics. The method comprises the steps: in a load model aspect, utilizing an air-conditioning load calculating model based on a double cage type rotor induction motor model and a static load calculating model which is mainly for illumination; and in a three phase load flow calculating model aspect, utilizing an abc three phase power balance equation and a 0 phase current balance equation for a load node, and using a current balance equation for both the abc three phase and 0 phase of a connection node at the low voltage side of a distribution transformer. The resident distribution unit area three phase unbalanced load flow calculating method taking regard of load characteristics can reduce the programming derivation calculated amount for three phase load flow calculation, and is easy for implementation. The resident distribution unit area three phase unbalanced load flow calculating method can accurately reflect the three phase unbalanced degree of a resident low voltage distribution unit area in various operating conditions, and can evaluate the influence on safe, high-quality economic operation of the power distribution network.

Description

technical field [0001] The invention relates to the field of electric power operation analysis, in particular to a calculation method for three-phase unbalanced power flow in a residential distribution station area considering load characteristics. Background technique [0002] The low-voltage distribution network is a link directly connected to users in the power system, and its safe and high-quality operation directly affects the normal power consumption of users. The low-voltage distribution network area composed of a 10kV step-down to 380V distribution transformer, a 380V outlet connected to its secondary side, and a low-voltage load is the basic form of a low-voltage distribution network. At present, in most low-voltage distribution stations in my country, due to the coexistence of three-phase power supply and single-phase power supply, the three-phase load access is uneven, the three-phase unbalanced operation is serious, and the three-phase voltage unbalance at the lo...

AI Technical Summary

Problems solved by technology

At present, in most low-voltage distribution stations in my country, due to the coexistence of three-phase power supply and single-phase power supply, the three-phase load access is uneven, the three-phase unbalanced operation is serious, and the three-phase voltage unbalance at the load point on the feeder is often Larger, seriously affecting the quality of the user's power supply voltage

In addition, the increase of the three-phase unbalance will also increase the current and active power loss of the neutral line, thus affecting the economical operation of the low-voltage distribution station area

Especially for a large number of low-voltage distribution stations for residents, since there are a large number of single-phase air-conditioning loads in the station area, the current and power of the air-conditioning load at start-up are several times larger than those at normal operation, and the instantaneous start-up tends to be further increased. Three-phase unbalance degree in low-voltage distribution station area

[0003] In the conventional three-phase unbalanced power flow calculation of the distribution network, the load adopts a constant power model that does not change with time and operating status, which does not reflect the changing characteristics of the actual load. The three-phase power flow calculation using the load node constant power model evaluates the distribution area The degree of three-phase unbalance in operation is often very different from the actual situation

Especially for the operating condition where the air conditioner load is started, since its current and power are several times higher than during normal operation, the calculation results of the three-phase power flow using the constant power model of the normal operating power value are very different from the actual grid status, and cannot accurately reflect Three-phase unbalance degree in low-voltage distribution station operation

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