Grid-connected switch driving coil wiring circuit of wind power converter

Abstract

The utility model discloses a grid-connected switch driving coil wiring circuit of a wind power converter. The grid-connected switch driving coil wiring circuit comprises a UPS, a group I load arranged between the input end of the UPS and a 380V power supply, and a group III load arranged at the output end of the UPS. The group I load comprises a grid-connected switch energy storage coil, a closing coil and an opening coil; the group III load comprises a grid-connected switch controller, an under-voltage trip coil and a converter control system; the control end of the converter control system is connected with three groups of relays; and a normally open contact of the relay is connected between any phase of 380V and the input end of the coil. According to the utility model, the capacity of the uninterruptible power supply used by the wind power converter is reduced, the cost is reduced, the backup time of the UPS is prolonged, the important load of the converter runs for a longer time when 380V power failure occurs, and the stability of the system during the power failure is improved; and the impact of the UPS output end is smaller, the fluctuation is smaller when the converter system is started, and the reliability of the converter control system is improved.

Description

Technical Field

[0001] This utility model belongs to the field of power electronics technology, specifically relating to a wiring circuit for the grid-connected switch drive coil of a wind power converter. Background Technology

[0002] Wind farms are generally located in remote areas. Due to the harsher environment compared to urban areas and the instability of the primary input side of the 1140V / 400V tower base transformer, the secondary side 380V is prone to frequent power outages. This causes the control system, which requires power from 380V, to lose power, resulting in the entire converter system stopping operation and greatly reducing the reliability of the converter.

[0003] Under the aforementioned operating conditions, it is necessary to ensure that the converter system does not lose control of the modules due to a brief power outage, which could lead to module damage. Therefore, the converter's control system needs a method to ensure continuous operation during a 380V power failure. Consequently, the industry standard is to use a UPS (Uninterruptible Power Supply) to power the grid-connected switch control, contactors, and control system within the converter, rather than directly relying on 380V power to ensure the converter system continues to operate reliably during power outages.

[0004] The loads connected to UPS units in existing wiring configurations mainly include the coils of the electric energy storage operating mechanism of high-current devices such as grid-connected switches, the closing coil of the grid-connected switches, the opening coil of the grid-connected switches, the undervoltage trip coil of the grid-connected switches, and the control system in the converter responsible for the converter's start-up, shutdown, and detection functions. In current technology, all of these loads are connected to the output side of the UPS, significantly increasing the capacity of the UPS used.

[0005] Since all loads are connected to the back end of the UPS, the load on the control system is very small. However, the instantaneous power of the drive coils of high-current devices such as grid-connected switches is much larger than that of the control system. Especially now that the power of a single unit is gradually increasing, it is often necessary to use two or more grid-connected circuit breakers in parallel. With multiple circuit breakers closing synchronously, the instantaneous power consumption increases several times. In order to support such a large load power, the corresponding UPS capacity is required to be very large. Therefore, the UPS selection is large and the cost is high; the backup time is reduced. If the power outage lasts too long, the wind farm maintenance personnel will not be able to get to the site in time to deal with it; the load starting power is too large, and the power fluctuation supplied to the control system becomes larger, affecting the stability of the system. Utility Model Content

[0006] This utility model is proposed to overcome the shortcomings of the existing technology, and its purpose is to provide a wiring circuit for the grid-connected switch drive coil of a wind power converter.

[0007] This utility model is achieved through the following technical solution:

[0008] A grid-connected switch drive coil wiring circuit for a wind power converter includes a UPS, a group I load, and a group III load. The group I load is located between the input terminal of the UPS and a 380V power supply, and the group III load is located at the output terminal of the UPS. The required power consumption of the group I load is directly supplied by the secondary output 380V power supply of the 1140 / 400V tower base transformer. The required power consumption of the group III load is supplied by the UPS. The 380V power supply is the secondary output 380V power supply of the 1140 / 400V tower base transformer.

[0009] The load group I includes a grid-connected switch energy storage coil, a grid-connected switch closing coil, and a grid-connected switch opening coil connected in parallel.

[0010] The load group III includes a grid-connected switch controller, an undervoltage trip coil, and a converter control system connected in parallel.

[0011] The control terminal of the converter control system is connected in parallel to coil control relays I, II, and III.

[0012] The normally open contact of the intermediate relay No. I of the coil control relay is connected between any phase of the 380V power supply and the input terminal of the grid-connected switch energy storage coil.

[0013] The normally open contact of the intermediate relay of coil II is connected between any phase of the 380V power supply and the input terminal of the closing coil of the grid-connected switch.

[0014] The normally open contact of the intermediate relay No. III of the coil control relay is connected between any phase of the 380V power supply and the input terminal of the grid-connected switch trip coil.

[0015] The beneficial effects of this utility model are:

[0016] This utility model provides a grid-connected switch drive coil wiring circuit for a wind power converter. The grid-connected switch drive coil wiring method greatly reduces the capacity of the uninterruptible power supply (UPS) used by the wind power converter (hereinafter referred to as the converter), solving the problem of product space congestion caused by excessively large UPS capacity and size, and reducing costs. It also extends the backup time of the UPS, allowing the important loads (control systems) of the converter to operate for a longer period of time during a 380V power outage, improving the stability of the system during the power outage, and giving wind farm maintenance personnel sufficient time to deal with the series of problems caused by the 380V power outage. The impact at the UPS output is smaller, and the fluctuation of important loads is smaller when the converter system starts up, improving the reliability of the converter control system. Attached Figure Description

[0017] Figure 1 This is the circuit diagram of this utility model.

[0018] in:

[0019] 1. UPS; 2. Group I load; 3. Low power load; 4. Grid-connected switch energy storage coil; 5. Grid-connected switch closing coil; 6. Grid-connected switch opening coil; 7. Grid-connected switch controller; 8. Undervoltage trip coil; 9. Converter control system; 10. No. I intermediate relay normally open contact; 11. No. II intermediate relay normally open contact; 12. No. III intermediate relay normally open contact; 13. No. I coil control relay; 14. No. II coil control relay; 15. No. III coil control relay.

[0020] For those skilled in the art, other related figures can be obtained from the above figures without any creative effort. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solution of this utility model, the technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments.

[0022] like Figure 1 As shown, a grid-connected switch drive coil wiring circuit for a wind power converter includes a UPS1, a group of loads 2 (I group), and a group of loads 3 (III group). The group of loads 2 is located between the input terminal of the UPS1 and a 380V power supply, and the group of loads 3 is located at the output terminal of the UPS1. The group of loads 2 is directly supplied with the required power by the secondary output 380V power supply of the 1140 / 400V tower base transformer. The group of loads 3 is supplied with the required power by the UPS1. The 380V power supply is the secondary output 380V power supply of the 1140 / 400V tower base transformer.

[0023] The load group 2 includes a grid-connected switch energy storage coil 4, a grid-connected switch closing coil 5, and a grid-connected switch opening coil 6 connected in parallel.

[0024] The load group 3 includes a grid-connected switch controller 7, an undervoltage trip coil 8, and a converter control system 9 connected in parallel.

[0025] The control terminal of the converter control system 9 is connected in parallel to coil control relay 13 (I), coil control relay 14 (II), and coil control relay 15 (III).

[0026] The normally open contact 10 of the intermediate relay of coil I control relay 13 is connected between any phase of the 380V power supply and the input terminal of the grid-connected switch energy storage coil 4; the normally open contact 11 of the intermediate relay of coil II control relay 14 is connected between any phase of the 380V power supply and the input terminal of the grid-connected switch closing coil 5.

[0027] The normally open contact 12 of the intermediate relay of coil III control relay 15 is connected between any phase of the 380V power supply and the input terminal of the grid-connected switch trip coil 6.

[0028] Figure 1 This patent only covers the loads related to the connection method described in this patent; the other 380V power supply loads in the converter are not included here.

[0029] The working principle of this utility model:

[0030] This utility model proposes to divide the load of the grid-connected switch into two parts. The first part of the load is the load that does not need to perform any action or maintain power supply under normal and brief 380V power outage conditions, namely the coil of the electric energy storage mechanism of the grid-connected switch, the closing coil of the grid-connected switch, and the opening coil of the grid-connected switch. The second part of the load is the load that needs to continue to maintain power supply and maintain the operation of the entire converter control system under the condition of brief power outage, namely the undervoltage trip coil of the grid-connected switch, the grid-connected switch controller, and the converter control system.

[0031] Since the first part of the load does not need to maintain power supply during a brief power outage, the first part of the load was moved from the output side of the UPS to the input side, and the required power was directly supplied by the 380V power supply. The second part of the load remained connected to the output side of the UPS.

[0032] The first part of the load only generates a corresponding action signal from the control system to the intermediate relay KA when needed. The normally open contact of KA then changes the energizing state of the coil accordingly. If the system is in a stopped state preparing to start, and a 380V power failure occurs, the system detects a 380V mains power anomaly and does not allow startup. Therefore, no closing command is sent to the grid-connected switch, meaning the closing coil absolutely does not need to operate at this time. If the system is in an operating state, and a 380V power failure occurs, the system detects a 380V mains power anomaly, reduces the load, and simultaneously sends commands to the trip coil and undervoltage release coil to trip the grid-connected switch. Although the trip coil is powered by the mains and will not operate in this power failure, the undervoltage release coil is powered by the UPS, ensuring reliable operation and thus reliably tripping the grid-connected switch. Therefore, moving the closing and trip coils of the grid-connected switch from the UPS downstream stage to the UPS upstream stage will not affect the reliable operation of the system.

[0033] The second part of the load, when the 380V power is lost, the entire control system is maintained by the power energy stored in the UPS itself to maintain the state of the control system before the power loss. During low voltage ride-through, the undervoltage release will also remain energized and will not cause the grid-connected switch to trip. When the 380V power supply is restored, the UPS is charged by the 380V while providing power to the control system.

[0034] The wiring method of this utility model changes the load distribution of the control system, reduces unnecessary loads on the UPS, and reduces the UPS capacity by changing the wiring of unnecessary loads, thereby improving the reliability of the converter control system.

[0035] This invention, without altering the operating state of the converter system itself, changes the load distribution method of the entire control section, connecting unnecessary loads to the input side of the UPS and altering the capacity of the selected UPS. The reduction in UPS capacity leads to lower costs and space savings. Simultaneously, with the reduced load on the UPS output side, the UPS only supplies power to the control system, making the converter control system more reliable and extending the UPS's backup power time. The entire converter control system (first part load, second part load) is no longer powered through an 1140V / 400V tower-based transformer-UPS configuration, but instead directly powered by a more stable mains power supply or a large-capacity energy storage device.

[0036] The applicant declares that the above description is only a specific embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present utility model fall within the protection and disclosure scope of the present utility model.

Claims

1. A wiring circuit for the grid-connected switch drive coil of a wind power converter, characterized in that: The system includes a UPS (1), a load group I (2), and a load group III (3). The load group I (2) is located between the input terminal of the UPS (1) and the 380V power supply, and the load group III (3) is located at the output terminal of the UPS (1). The load group I (2) includes a grid-connected switch energy storage coil (4), a grid-connected switch closing coil (5), and a grid-connected switch opening coil (6) connected in parallel. The load group III (3) includes a grid-connected switch controller (7), an undervoltage trip coil (8), and a converter control system (9) connected in parallel. The control terminal of the converter control system (9) is connected to the coil control relays I (13), II (14), and III (15) connected in parallel.

2. The grid-connected switch drive coil wiring circuit of the wind power converter according to claim 1, characterized in that: The required power consumption of load group I (2) is directly provided by the secondary output 380V power supply of the 1140 / 400V tower base transformer; the required power consumption of load group III (3) is provided by UPS (1).

3. The grid-connected switch drive coil wiring circuit of the wind power converter according to claim 1, characterized in that: The 380V power supply is the secondary output 380V power supply of the 1140 / 400V tower base transformer.

4. The grid-connected switch drive coil wiring circuit of the wind power converter according to claim 1, characterized in that: The normally open contact (10) of the intermediate relay of the No. I coil control relay (13) is connected between any phase of the 380V power supply and the input terminal of the grid-connected switch energy storage coil (4).

5. The grid-connected switch drive coil wiring circuit of the wind power converter according to claim 1, characterized in that: The normally open contact (11) of the intermediate relay of coil control relay II (14) is connected between any phase of the 380V power supply and the input terminal of the grid-connected switch closing coil (5).

6. The grid-connected switch drive coil wiring circuit of the wind power converter according to claim 1, characterized in that: The normally open contact (12) of the intermediate relay of coil control relay (15) is connected between any phase of the 380V power supply and the input terminal of the grid-connected switch trip coil (6).

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