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Distribution network stability improvement system and method for parallel operation of multiple port machines

A technology to upgrade the system and distribution network, which is applied in the field of port distribution network, can solve the problems of distribution system instability and achieve the effect of improving stability

Inactive Publication Date: 2018-11-27
NARI TECH CO LTD +4
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art, provide a system and method for improving the stability of the distribution network with multiple port machines running in parallel, and solve the problem of power distribution system instability in the parallel operation of multiple port machines in the prior art question

Method used

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  • Distribution network stability improvement system and method for parallel operation of multiple port machines
  • Distribution network stability improvement system and method for parallel operation of multiple port machines
  • Distribution network stability improvement system and method for parallel operation of multiple port machines

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] Such as figure 1As shown, including: multiple frontier substations, a central substation that supplies power to multiple frontier substations, 10kV / 690V transformers installed in the frontier substations, and 690V / 440V transformers corresponding to each distribution subsystem , AC / DC converter and DC / AC inverter. The secondary side of the 10kV / 690V transformer is connected to the primary side of each 690V / 440V transformer through the 690V bus bar, and the secondary side of the 690V / 440V transformer is connected to the AC side of the AC / DC converter of the corresponding distribution subsystem. AC / DC The DC side of the converter is connected in series with the DC / AC inverter to supply power to each load of the distribution subsystem.

[0043] Using Matlab / Simulink to build a simulation model of the port distribution network including six working conditions of the bridge, to simulate the voltage, current and instability conditions of important nodes in the process of pote...

Embodiment 2

[0048] The difference between Embodiment 2 and Embodiment 1 is that when it is detected that the total feed energy of the 690V bus is greater than or equal to the set threshold power, a switchable inductance is connected in parallel on the 690V bus. The value range of the switchable inductance is: It is recommended that the reactive power under the rated voltage is not less than 10%P max . In this example, the inductance value of the switchable inductor is preferably 17.83mH.

[0049] Such as Figure 5 As shown, it is the waveform diagram of the inner loop of the controller and the modulation degree when the inductance is connected in parallel on the 690V bus. It can be seen that the controller of the DC / AC inverter is stable and does not diverge (the modulation degree M is less than the maximum allowable modulation degree), and the parallel connection can be switched on and off. After the inductance, a certain amount of reactive power is absorbed at the 690V bus, causing th...

Embodiment 3

[0052] The third embodiment differs from the first embodiment in that when it is detected that the total energy fed to the 690V bus is greater than or equal to the set threshold power, a switchable energy storage device is connected in parallel on the 690V bus. The energy storage device that can be switched on and off can absorb the active power of multi-frequency converters, so that the total fed power is less than the critical power value of instability.

[0053] If the fed energy power is less than the set threshold power, the switchable energy storage device will be withdrawn.

[0054] The present invention also provides a distribution network stability improvement method for multi-port machine parallel operation, including: a 10kV / 690V transformer installed in the frontier substation, a 690V / 440V transformer corresponding to each distribution sub-system, AC / DC converter and DC / AC inverter; the secondary side of the 10kV / 690V transformer is connected to the primary side o...

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Abstract

The invention discloses a distribution network stability improvement system and method for the parallel operation of multiple port machines. The distribution network stability improvement system comprises a 10kV / 690V transformer arranged in a leading-edge substation, 690V / 440V transformers configured respectively corresponding to distribution subsystems, AC / DC current transformers and DC / AC frequency transformers, wherein the secondary side of the 10Kv / 690V transformer is connected with the primary side of each 690V / 440V transformer through a 690V bus, the 690V bus is further connected with apower detection device used for energy feedback power detection, and meanwhile, the 690V bus is also connected with a switchable resistor, a switchable inductor or a switchable energy storage device in parallel; and if the energy feedback power at the 690V bus side is greater than or equal to the set threshold power, the switchable resistor, the switchable inductor or the switchable energy storagedevice is switched on and enabled to be connected with the 690V bus in parallel. The distribution network stability improvement system can solve a technical problem that multiple sets of port machineequipment are simultaneously instable in energy feedback control at the port, and improves the stability of a distribution system during energy feedback.

Description

technical field [0001] The invention relates to the technical field of port distribution network, in particular to a system and method for improving the stability of a distribution network in which multiple port machines operate in parallel. Background technique [0002] The port distribution network generally supplies power to each distribution sub-system (sub-substation) through the general step-down substation (central substation). Machine equipment mainly includes quay cranes and field cranes. [0003] In the port machinery distribution subsystem, multiple sets of port machinery equipment are connected in parallel to the AC bus of the distribution network. When the grid impedance is high, the multi-port machine parallel system is prone to unstable conditions; especially in the multi-port machine power distribution system on a weak grid, the stability problem is more prominent. [0004] The typical system architecture of a conventional AC distribution network includes: ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/50H02J3/24
CPCH02J3/24H02J3/50H02J2203/20
Inventor 俞拙非武迪骆健洪丹陈永华陈璐瑶邓任任孙厚涛
Owner NARI TECH CO LTD