Linkage protection system and method for photovoltaic power station

Patent metadata

Field	Value
Publication number	US-12199566-B2
Application number	US-202217896730-A
Country	US
Kind code	B2
Filing date	Aug 26, 2022
Priority date	Aug 14, 2020
Publication date	Jan 14, 2025
Grant date	Jan 14, 2025

Abstract

A linkage protection system includes an inverter, an anti-potential-induced degradation (PID) apparatus, and an insulation-monitoring apparatus. The anti-PID apparatus is configured to inject a voltage into an input end or an output end of the inverter, to increase or decrease a voltage-to-earth of a photovoltaic system. The insulation-monitoring apparatus is configured to inject an insulation-monitoring voltage into a direct current (DC) side or an alternating current (AC) side of the inverter. The anti-PID apparatus and the insulation-monitoring apparatus directly or indirectly communicate with each other, to learn of information about whether a peer apparatus is operating, and perform linkage control. The anti-PID apparatus and the insulation-monitoring apparatus operate in different time periods.

First claim

What is claimed is:

1. A linkage protection system and comprising:
an inverter comprising an inverter input end and an inverter output end;
an anti-potential-induced degradation (PID) apparatus coupled to the inverter, wherein the anti-PID apparatus is configured to:
inject a first voltage into the inverter input end to increase a voltage-to-earth potential of a photovoltaic system; and
inject a second voltage into the inverter output end to decrease the voltage-to-earth potential of the photovoltaic system; and

an insulation-monitoring apparatus coupled to the inverter and to the anti-PID apparatus and comprising a first dry contact, wherein the insulation-monitoring apparatus is configured to directly communicate with the anti-PID apparatus via the first dry contact, and wherein the insulation-monitoring apparatus is further configured to:
inject an insulation-monitoring voltage into an inverter direct current (DC) side or into an inverter alternating current (AC) side, wherein the inverter input end is coupled to the inverter DC side, and wherein the inverter output end is coupled to the inverter AC side;
communicate with the anti-PID apparatus to perform linkage control; and
alternately operate the anti-PID apparatus and the insulation-monitoring apparatus in different time periods based on communication with the anti-PID apparatus.

2. The linkage protection system of claim 1 , wherein the anti-PID apparatus is configured to operate while the insulation-monitoring apparatus does not operate in a first time period and when the anti-PID apparatus and the insulation-monitoring apparatus alternately operate in different time periods, and wherein the insulation-monitoring apparatus is configured to operate while the anti-PID apparatus does not operate in a second time period and when the anti-PID apparatus and the insulation-monitoring apparatus alternately operate in different time periods.

3. The linkage protection system of claim 1 , wherein the anti-PID apparatus and the insulation-monitoring apparatus are configured to directly or indirectly communicate via a Modbus Protocol.

4. The linkage protection system of claim 1 , wherein the anti-PID apparatus and the insulation-monitoring apparatus are configured to directly or indirectly communicate with each other via the first dry contact.

5. The linkage protection system of claim 4 , wherein the anti-PID apparatus comprises a second dry contact, and wherein the first dry contact is configured to connect with the second dry contact when the anti-PID apparatus and the insulation-monitoring apparatus directly communicate with each other.

6. The linkage protection system of claim 5 , wherein the second dry contact is a digital output (DO) contact, wherein the first dry contact is a digital input (DI) contact, and wherein the anti-PID apparatus is further configured to:
control the DO contact to be in a first state to enable the insulation-monitoring apparatus to monitor a status of the DI contact to stop operating; and
control the DO contact to be in a second state to enable the insulation-monitoring apparatus to monitor the status of the DI contact to start operating.

7. The linkage protection system of claim 5 , wherein the second dry contact is a digital input (DI) contact, wherein the first dry contact is a digital output (DO) contact, and wherein the insulation-monitoring apparatus is further configured to:
control the DO contact to be in a first state to enable the anti-PID apparatus to monitor a status of the DI contact to stop operating; and
control the DO contact to be in a second state to enable the anti-PID apparatus to monitor the status of the DI contact to start operating.

8. The linkage protection system of claim 4 , further comprising a data collection apparatus configured to communicate with the anti-PID apparatus, wherein the data collection apparatus comprises a second dry contact, and wherein the second dry contact and the first dry contact are configured to connect when the anti-PID apparatus and the insulation-monitoring apparatus indirectly communicate with each other.

9. The linkage protection system of claim 8 , wherein the second dry contact is a digital output (DO) contact, wherein the first dry contact is a digital input (DI) contact, and wherein the data collection apparatus is further configured to:
control the DO contact to be in a first state to enable the insulation-monitoring apparatus to monitor a status of the DI contact to stop operating; and
control the DO contact to be in a second state to enable the insulation-monitoring apparatus to monitor the status of the DI contact to start operating.

10. The linkage protection system of claim 8 , wherein the second dry contact is a digital input (DI) contact, wherein the first dry contact is a digital output (DO) contact, and wherein the insulation-monitoring apparatus is further configured to:
control the DO contact to be in a first state to enable the data collection apparatus to monitor a status of the DI contact to notify the anti-PID apparatus to stop operating; and
control the DO contact to be in a second state to enable the data collection apparatus to monitor the status of the DI contact to notify the anti-PID apparatus to start operating.

11. The linkage protection system of claim 1 , wherein the anti-PID apparatus is external to the inverter, wherein the linkage protection system comprises a plurality of inverters, wherein inverter output ends of the plurality of inverters are connected in parallel, and wherein the plurality of inverters share a same anti-PID apparatus.

12. The linkage protection system of claim 1 , wherein the anti-PID apparatus is internal to the inverter.

13. The linkage protection system of claim 12 , wherein the linkage protection system comprises a plurality of inverters, wherein inverter output ends of the plurality of inverters are connected in parallel, wherein each of the plurality of inverters comprises one anti-PID apparatus, wherein each anti-PID apparatus in the plurality of inverters communicates with the insulation-monitoring apparatus, and wherein anti-PID apparatuses of all the plurality of inverters synchronously start operating or synchronously stop operating.

14. The linkage protection system of claim 1 , further comprising:
a DC-DC converter comprising a DC-DC converter first end and a DC-DC converter second end, wherein the DC-DC converter first end is connected to the inverter DC side; and
a battery connected to the DC-DC converter second end, wherein the insulation-monitoring apparatus is integrated inside the DC-DC converter.

15. The linkage protection system of claim 1 , further comprising:
a battery;
a DC-DC converter comprising a DC-DC converter first end, a DC-DC converter second end connected to the battery, and a DC-DC converter dry contact; and
a power conversion system comprising:
a first power conversion system end is connected to the AC side;
a second power conversion system end connected to the DC-DC converter first end; and
a power conversion system dry contact, wherein the second power conversion system end is connected to the DC-DC converter first end, and wherein the DC-DC converter second end is connected to the battery,

wherein the insulation-monitoring apparatus comprises:
a first insulation-monitoring apparatus disposed inside the DC-DC converter; and
a second insulation-monitoring apparatus disposed inside the power conversion system,

wherein the DC-DC converter dry contact is configured to communicate with the power conversion system dry contact via the DC-DC converter dry contact or t

Assignees

• Huawei Digital Power Tech Co Ltd

Inventors

• Wan Song
• Gao Yongbing
• Wang Xun
• Zhang Yanzhong
• Wu Zhipeng

Classifications

• H02J2101/22

  Solar energy · CPC title

• H02S40/32

  comprising DC/AC inverter means associated with the PV module itself, e.g. AC modules · CPC title

• H02S50/10 Primary

  Testing of PV devices, e.g. of PV modules or single PV cells (testing of semiconductor devices during manufacturing {H10P74/00}) · CPC title

• H02J3/381

  Dispersed generators · CPC title

• Y02E10/50

  Photovoltaic [PV] energy · CPC title