CN-121984242-A - Flexible ring closing method and device based on FTU equipment

CN121984242ACN 121984242 ACN121984242 ACN 121984242ACN-121984242-A

Abstract

The invention discloses a flexible ring closing method and device based on FTU equipment, which belong to the field of power distribution network control and are suitable for a flexible ring closing device; the flexible ring closing device comprises an FTU device, a voltage source converter, a direct current supporting capacitor, a first bypass switch, a ring closing switch and a second bypass switch which are sequentially connected in series on a power transmission line, wherein the method comprises the steps that the FTU device charges the direct current supporting capacitor, starts flexible ring closing operation, collects voltage information on the power transmission lines on two sides of the flexible ring closing device, and on-off state information of the first bypass switch, the ring closing switch and the second bypass switch, judges whether ring closing conditions are met according to the voltage information and the on-off state information, and if yes, controls the voltage source converter to execute and complete flexible ring closing. By implementing the invention, the problem of dependence of the flexible ring closing device on external equipment in the prior art can be solved.

Inventors

DAN YANGQING
WANG WENHAO
SUN LICHENG
FEI YANAN
TANG AIHONG
WANG JUN
GU YILEI
HUANG JINHUA
WANG CHENXUAN
ZOU LI
CHEN QINGYUE
XU ENCHAO

Assignees

国网浙江省电力有限公司经济技术研究院
国网浙江省电力有限公司

Dates

Publication Date: 20260505
Application Date: 20260407

Claims (10)

1. The flexible ring closing method based on the FTU equipment is characterized by being suitable for a flexible ring closing device, wherein the flexible ring closing device comprises the FTU equipment, a voltage source converter, a direct current supporting capacitor, a first bypass switch, a ring closing switch and a second bypass switch which are sequentially connected in series and arranged on a power transmission line, wherein an alternating current output end of the voltage source converter is connected between the first bypass switch and the second bypass switch in series; the flexible ring closing method based on the FTU equipment comprises the following steps: The FTU equipment charges the direct-current supporting capacitor, starts flexible loop closing operation, collects voltage information on power lines on two sides of the flexible loop closing device and opening and closing state information of the first bypass switch, the loop closing switch and the second bypass switch, judges whether loop closing conditions are met according to the voltage information and the opening and closing state information, and if yes, controls the voltage source converter to execute and complete flexible loop closing.
2. The flexible ring closing method based on the FTU equipment of claim 1, wherein the FTU equipment comprises a telemetry module, a remote signaling module and an intelligent controller, wherein the telemetry module is connected with a voltage sampling point of the power transmission line; the collection flexible closes voltage information on the transmission line of ring device both sides, and the open and close state information of first bypass switch, closed ring switch and second bypass switch includes: The remote measuring module collects voltage information on power transmission lines at two sides of the flexible ring closing device and sends the voltage information to the intelligent controller; the remote signaling module acquires the opening and closing state information of the first bypass switch, the ring closing switch and the second bypass switch, and sends the opening and closing state information to the intelligent controller.
3. The flexible ring closing method based on the FTU equipment of claim 2, wherein the FTU equipment further comprises a power module, a capacitor bank, a power module and a power module, wherein the capacitor bank is connected with the direct current support capacitor; the FTU device charges the dc support capacitor, starts a flexible loop closing operation, and includes: and the capacitor bank charges the direct-current supporting capacitor and starts flexible loop closing operation.
4. The flexible ring closing method based on the FTU device of claim 3, wherein the power module further comprises a charging unit, wherein the input end of the charging unit is connected to a power transmission line, and the output end of the charging unit is connected to the capacitor bank; and the power supply module can supplement power to the capacitor bank by taking energy from the power transmission line through the charging unit after closing the ring.
5. The flexible ring closing method based on the FTU equipment of claim 3, wherein the power module further comprises a voltage stabilizing module, wherein the input end of the voltage stabilizing module is connected to the capacitor bank, and the output end of the voltage stabilizing module is respectively connected to the telemetry module, the remote signaling module, the remote control module and the intelligent controller and is used for providing stable working voltage.
6. The flexible loop closing method based on the FTU equipment of claim 2, wherein the telemetry module comprises a voltage transformer and an analog-to-digital conversion circuit, wherein the input end of the voltage transformer is connected to a voltage sampling point of a power transmission line, and the output end of the voltage transformer is connected to the analog-to-digital conversion circuit; the telemetry module collects voltage information on power transmission lines on two sides of the flexible ring closing device and comprises the following components: the voltage transformer collects analog voltage signals of the voltage sampling points and sends the analog voltage signals to the analog-to-digital conversion circuit; And the analog-to-digital conversion circuit converts the analog voltage signal into a digital signal to obtain the voltage information and sends the voltage information to the intelligent controller.
7. The flexible ring closing method based on FTU apparatus of claim 2, wherein the determining whether the ring closing condition is satisfied according to the voltage information and the open/close state information comprises: the intelligent controller calculates a voltage difference value between voltage sampling points according to the voltage information, judges whether the first bypass switch and the second bypass switch are in a closed state or not and the ring closing switch is in an open state or not based on the opening and closing state information, and judges whether the ring closing condition is met if all the conditions are met.
8. The FTU apparatus-based flexible loop closing method of claim 7, wherein the voltage differential comprises a direct axis voltage differential and a quadrature axis voltage differential; The calculating the voltage difference between the voltage sampling points according to the voltage information comprises the following steps: Respectively carrying out coordinate transformation on alternating voltage on power transmission lines at two sides of the flexible ring closing device to obtain respective direct-axis voltage components and quadrature-axis voltage components at two sides; and calculating the difference value of the direct axis voltage components at two sides to obtain a direct axis voltage difference value, and calculating the difference value of the quadrature axis voltage components at two sides to obtain a quadrature axis voltage difference value.
9. The flexible ring closing method based on the FTU equipment of claim 8, wherein the FTU equipment further comprises a remote control module, wherein the remote control module is respectively connected with the IGBT driving ends of the voltage source converters; the control voltage source converter performs and completes flexible loop closing, comprising: The remote control module takes the direct-axis voltage difference value as a direct-axis compensation component after inverting the direct-axis voltage difference value, takes the quadrature-axis voltage difference value as a quadrature-axis compensation component after inverting the quadrature-axis voltage difference value, synthesizes a compensation voltage vector according to the direct-axis compensation component and the quadrature-axis compensation component, generates a pulse width modulation signal based on the amplitude and the phase angle of the compensation voltage vector, takes the pulse width modulation signal as the trigger pulse, and sends the trigger pulse to the voltage source converter, so that the voltage source converter generates compensation voltage according to the trigger pulse and injects the compensation voltage into a power transmission line to complete flexible loop closing.
10. The flexible ring closing device based on the FTU equipment is characterized by comprising the FTU equipment, a voltage source converter, a direct current supporting capacitor, a first bypass switch, a ring closing switch and a second bypass switch, wherein the first bypass switch, the ring closing switch and the second bypass switch are sequentially arranged on a power transmission line in series; The FTU equipment charges the direct-current supporting capacitor, starts flexible loop closing operation, collects voltage information on power lines on two sides of the flexible loop closing device and opening and closing state information of the first bypass switch, the loop closing switch and the second bypass switch, judges whether loop closing conditions are met according to the voltage information and the opening and closing state information, and if yes, controls the voltage source converter to execute and complete flexible loop closing.

Description

Flexible ring closing method and device based on FTU equipment Technical Field The invention belongs to the field of power distribution network control, and relates to a flexible ring closing method and device based on FTU equipment. Background In an automatic system of a power distribution network, a flexible loop closing technology is used as a means for improving the power supply reliability, compensation voltage is injected through a voltage source converter, no-impact parallel operation between two feeder lines is realized, and the flexible loop closing technology is applied to partial high-reliability power supply areas. The existing flexible ring closing device is generally composed of an independent voltage source converter, a monitoring module, a communication unit, a control module and a standby power supply (such as UPS), the starting energy of the device depends on an external storage battery or a special energy taking circuit, voltage and switch state information are required to be acquired through an external transformer and transmitted to a controller through a communication bus, and a control instruction is modulated and then output to a driving circuit. The multi-module separation architecture not only increases the volume and cost of equipment, but also reduces the reliability of the system due to a plurality of interfaces, is difficult to deploy in a scene without independent communication and control resources, and limits the popularization and application of the flexible ring closure technology in stock distribution networks. Disclosure of Invention The application provides a flexible ring closing method and device based on FTU equipment, which can solve the problem of dependence of a flexible ring closing device on external equipment in the prior art. In order to achieve the aim, the invention provides a flexible ring closing method based on FTU equipment, which is suitable for a flexible ring closing device, wherein the flexible ring closing device comprises the FTU equipment, a voltage source converter, a direct current support capacitor, a first bypass switch, a ring closing switch and a second bypass switch which are sequentially arranged on a power transmission line in series, wherein an alternating current output end of the voltage source converter is connected between the first bypass switch and the second bypass switch in series; the flexible ring closing method based on the FTU equipment comprises the following steps: The FTU equipment charges the direct-current supporting capacitor, starts flexible loop closing operation, collects voltage information on power lines on two sides of the flexible loop closing device and opening and closing state information of the first bypass switch, the loop closing switch and the second bypass switch, judges whether loop closing conditions are met according to the voltage information and the opening and closing state information, and if yes, controls the voltage source converter to execute and complete flexible loop closing. Compared with the prior art, the method has the advantages that the FTU equipment, the voltage source converter, the direct-current supporting capacitor and the three switches are integrated in the same flexible ring closing device, direct connection is built between the FTU equipment and the direct-current supporting capacitor, and between the FTU equipment and the direct-current supporting capacitor, the direct-current supporting capacitor and the direct-current power transmission line, so that an external device is not required to be externally connected, the FTU equipment charges the direct-current supporting capacitor to start flexible ring closing operation, meanwhile, voltage information of the two power transmission lines and open-close state information of the three switches are collected, ring closing conditions are judged based on the voltage information and the open-close state information, if the voltage source converter is met, the voltage source converter is controlled to execute and complete flexible ring closing, and the integral cooperation of the three aspects of energy supply, state sensing and control are executed through the FTU equipment is omitted, independent monitoring, communication, control and standby power supply modules in a traditional scheme are omitted, system deployment convenience and running reliability are improved, and dependence of the flexible ring closing device on external devices in the prior art is solved. In some embodiments of the first aspect of the present application, the FTU device comprises a telemetry module, a telemetry module and an intelligent controller, wherein the telemetry module is connected with a voltage sampling point of the power transmission line; the collection flexible closes voltage information on the transmission line of ring device both sides, and the open and close state information of first bypass switch, closed ring switch and second bypass switch i