Function highlights The overhead line automation solution covers a wide range of applications including single and dual power supply systems. The overhead line automation solution covers rural areas, the last mile of intelligent power distribution. It can realize the FDIR function without establishing a communication and SCADA system,. Therefore, less construction funds are needed. The solution has a high degree of expandability and flexibility. It supports the extension of a communication and SCADA System. The application of recloser automation solutions allows for restoration of faults within seconds, achieving a fast power supply restoration. It can realize uninterrupted power supply to ensure the reliability of electricity for important customers, and improve the quality of power services.

Overview:

Overhead line distribution automation solutions enable rapid detection, isolation and restoration of feeder faults through the cooperation between reclosers, or between circuit breakers and load break switches.

Overhead line distribution automation solutions are mainly divided into local and centralized types: the local type does not depend on the communication and SCADA systems. It can realize various logical actions through the local FTU; the centralized type needs to establish communication and SCADA, the master station sends control commands to the intelligent terminal, so as to realize the distribution network automation functions.

Our self-developed overhead line automation solutions, mainly local and partly centralized, with the innovative combination of both types, will meet the needs of customers for automation with different grid topologies. The solutions are mainly: Current-counter solution, voltage-time solution, loop automation solution and auto-changeover solution.

Overhead Line Distribution Automation Solution Introduction:

A. Current-counter solution

The current-counter solution is usually used for radial lines, and the function is realized by the local FTU. When the logic conditions are met, the load break switch (sectionalizer) will be automatically open and locked out. The load break switch uses the detected current signal as the basis for logic judgment.

When over-current and ground fault of a line occurs, the upstream recloser or circuit breaker will execute open action. The load break switch will count the number of interruptions occurring on the fault current (over-current and ground fault). Once the number reaches a preselect value, it automatically opens and locks out when there is no voltage and current to isolate the permanently faulty section. Meanwhile, if the upstream recloser or circuit breaker closes again, the power supply of the non-faulty sections will be restored.

The whole process takes less than 1 minute.

Users may, according to their need, choose to establish communication and SCADA system for remote monitoring and control.

Overhead Line Distribution Solution

B. Voltage-time solution

The voltage-time solution is usually used for single ring network lines, including section switch and interconnection switch. The function is realized by the local FTU. When the logic conditions are met, the load break switch (section switch or interconnection switch) will be automatically open and locked out. The load break switch uses the detected voltage signal as the basis for logic judgment.

When over-current and ground fault of a line occurs, the upstream recloser or circuit breaker will execute open action. When the section switch detects the absence of voltage of both sides, it opens immediately. After the upstream recloser or circuit breaker has reclosed once, when voltage is detected on the power supply side of the adjacent section switch, it will be activated after X delay time. If the signal of voltage absence is detected again within X delay time, and the section switch keeps being open and the closing is locked out, it indicates that the fault occurs on the upstream section of the section switch. If a voltage is detected on the power supply side during the X delay time, the section switch will be closed after the X delay time. After it has closed for Y delay time, it will be activated. If a voltage absence signal is detected again on both sides of the section switch during the Y delay time, and the switch opens and locks out, it indicates that the fault occurs on the downstream section of this section switch. If there is voltage on both sides during the Y delay time, and the sectional switch is closed successfully, it indicates that there is no fault on the upstream and downstream sections of this section switch.

The interconnection switch is at the normally open point of the single ring network. In the normal state, both sides of it have voltage. So it remains open and locked out. When the interconnection switch detects an absence of voltage on one side, it waits for XL delay time. If the absence of voltage on one side persists during the XL delay time, and the interconnection switch closes after the XL delay time, it indicates that a permanent fault has occurred on one side of the line. The transfer of power should be executed. If in the XL delay time a voltage signal is detected on the voltage absence side, the XL delay time should be cleared and the Z time limit confirmation should be conducted. If voltage continues to exist within the Z time limit and the contact switch is kept open and locked out, it indicates that a permanent fault occurs on the adjacent line.

Through the above logic process, the load break switch (section switch and interconnection switch) finally achieves faulty section isolation and restore of power supply in the non-faulty sections, and the processing time of the whole process is less than 1 minute.

Users may, according to their need, choose to establish communication and SCADA system for remote monitoring and control.