The independent control technology without tie line of inverter power supply is to realize the parallel technology without signal line between units by referring to the self-synchronization and voltage sag characteristics of synchronous generator. It is also one of the current advanced parallel control technologies.

Two advantages of inverter power supply

1. Reduced maintenance expenditure of system operation

① In the integrated autonomous substation now in operation, a background supervision and control microcomputer is usually set up. Most of the communication devices are microwave and optical fiber machines. The working power supply of this type of supervision and control and communication devices is AC power supply, which needs to meet the requirements of continuous power supply to achieve the purpose of "four remotes".

② The investment cost is saved. Different devices must be separately equipped with continuous power supply and battery pack. The power supply installed in the substation can directly use the large-capacity battery of the DC power system used to supply AC power.

Τροφοδοτικό inverter

③ The maintenance times and expenses are reduced, and the multiple investment of battery pack is prevented.

2. Improve safety performance.

It can prevent the impact of power grid fluctuation on the load bearing, fully meet the requirements of RTU, communication device, microcomputer and other devices in substation substation for working power supply, and can also prevent the power board burning event caused by lightning and other high voltage phenomena, improving the safety characteristics of the load bearing.

Comparing the application of the above control strategies in the parallel operation system of inverter power supply, considering its operation performance and reliability, the inverter power supply system with independent control without tie line is the optimal scheme. In this control system, each inverter power supply module is controlled independently, without the interconnection signal line between modules, and only the output of each module is directly connected to the micro-network. The synchronization and current sharing control between each module is only based on the system control strategy inside the sub-module, which can completely isolate the electrical connection of the control system between each inverter power supply. Therefore, the system structure is simple, the installation and maintenance is more convenient, and the system capacity expansion is convenient, Χαμηλό κόστος, more reliable parallel operation.