SVG system with 35kV single-phase grounding protection function

Abstract

The utility model discloses an SVG (Static Var Generator) system with a 35kV single-phase grounding protection function, which comprises a grid-connected switch, a zero sequence current transformer, an incoming line isolating switch, a soft start switch, a soft start resistor, an air-core reactor and a current Hall sensor, the output side of the grid-connected switch passes through the zero sequence current transformer through a cable and is connected to the input side of the isolation switch, the output side of the isolation switch is connected to the input side of the soft start switch, and the soft start switch is connected in parallel with a soft start resistor; the output side of the soft start switch is connected to the input side of the air-core reactor, the output side of the air-core reactor penetrates through the current Hall sensor through a cable and is connected to the wire inlet of the SVG equipment body, the system realizes SVG primary system loop single-phase ground fault detection, a high-voltage power supply can be quickly cut off when the single-phase ground fault occurs, and the fault detection efficiency is improved. Interlocking faults caused by single-phase grounding faults are effectively avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of reactive power compensation equipment, in particular to an SVG system with a 35kV single-phase-to-ground protection function. Background Art

[0002] In recent years, the country has vigorously developed new clean energy power generation. As a result, the number of new energy power stations has increased, and the demand for on-site reactive power in new energy power stations has also arisen. SVG, as a large-capacity reactive power compensation device, has fast dynamic response speed and gradually improved technical maturity. It can always provide reactive power support for the power grid online. It is currently widely used in new energy sites.

[0003] Most SVGs used in new energy power stations are star-connected, with the neutral point being an ungrounded power device. However, in current domestic new energy power stations, the 35kV low-voltage side of the power station is mostly a neutral point grounding system with a small resistance, and the SVG branch and the power grid system are mostly electrically connected through power cables. Once a single-phase to ground fault occurs due to a cable terminal breakdown, the existing SVG control system cannot detect the fault in time, which will cause a short-circuit current to flow through the SVG charging circuit for a period of time, greatly increasing the risk of overload and burning of the soft start resistor. Utility Model Content

[0004] The technical problem to be solved by the utility model is to propose an SVG system with a 35kV single-phase-to-ground protection function. The SVG system with a 35kV single-phase-to-ground protection function realizes single-phase-to-ground fault detection in the SVG system circuit, and can quickly cut off the high-voltage power supply when a single-phase-to-ground fault occurs, effectively avoiding interlocking faults caused by the single-phase-to-ground fault.

[0005] In order to solve the above technical problems, the utility model provides an SVG system with a 35kV single-phase-to-ground protection function, including a grid-connected switch, a zero-sequence current transformer, an isolating switch, a soft-start switch, a soft-start resistor, an air-core reactor, a current Hall sensor and an SVG device body. The input side of the grid-connected switch is connected to the 35kV busbar of the new energy station, the output side of the grid-connected switch is connected to the input side of the isolating switch through a cable passing through the zero-sequence current transformer, the output side of the isolating switch is connected to the input side of the soft-start switch, the soft-start switch is connected in parallel with a soft-start resistor, the output side of the soft-start switch is connected to the input side of the air-core reactor, the output side of the air-core reactor is connected to the incoming line of the SVG device body through a cable passing through the current Hall sensor, the secondary side of the zero-sequence current transformer is connected to the input side of the isolating current transformer through a sampling line, the output side of the isolating current transformer is connected to the SVG controller of the SVG device body, the SVG controller is connected to the grid-connected switch, and the 35kV busbar of the new energy station is grounded through a resistor.

[0006] Preferably, the 35kV busbar of the new energy station is connected to the power grid through a step-up transformer to output electric energy, and the neutral point on the 35kV busbar line of the new energy station is grounded through a resistor.

[0007] Preferably, the SVG controller is connected to the opening coil of the grid-connected switch via an intermediate relay KA.

[0008] Preferably, the current Hall sensor and the isolation current transformer are installed inside the SVG device body, and the zero-sequence current transformer is installed on the output side of the grid-connected switch.

[0009] After adopting the above system, the SVG system with 35kV single-phase-to-ground protection function includes a grid-connected switch, a zero-sequence current transformer, an incoming line disconnector, a soft-start switch, a soft-start resistor, an air-core reactor, a current Hall sensor and an SVG device body. The input side of the grid-connected switch is connected to the 35kV busbar of the new energy station, and the output side of the grid-connected switch is connected to the input side of the disconnector through a cable passing through the zero-sequence current transformer, and the output side of the disconnector is connected to the input side of the soft-start switch. The soft-start switch is connected in parallel with a soft-start resistor, and the output side of the soft-start switch is connected to the input side of the air-core reactor. The output side of the reactor is connected to the incoming line of the SVG device body through a cable passing through a current Hall sensor, the secondary side of the zero-sequence current transformer is connected to the input side of the isolation current transformer through a sampling line, the output side of the isolation current transformer is connected to the SVG controller of the SVG device body, the SVG controller is connected to the grid-connected switch, and the 35kV busbar of the new energy station is grounded through a resistor; the SVG system with a 35kV single-phase to ground protection function realizes single-phase to ground fault detection of the SVG system loop, and can quickly cut off the high-voltage power supply when a single-phase to ground fault occurs, effectively avoiding interlocking faults caused by single-phase to ground faults. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is the overall circuit diagram of an SVG system with 35kV single-phase-to-ground protection function of the utility model;

[0011] Figure 2 This is a function realization circuit diagram of an SVG system with 35kV single-phase-to-ground protection function according to the utility model.

[0012] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0013] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer and more understandable, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0014] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "front", "back", "left", "right", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0015] Embodiment 1

[0016] See also Figure 1 , Figure 1 This is the overall circuit diagram of an SVG system with 35kV single-phase-to-ground protection function of the utility model;

[0017] The present embodiment discloses an SVG system with a 35kV single-phase-to-ground protection function, comprising a grid-connected switch 2, a zero-sequence current transformer 3, an isolating switch 4, a soft-start switch 5, a soft-start resistor 7, an air-core reactor 6, a current Hall sensor 8 and an SVG device body 10. The input side of the grid-connected switch 2 is connected to the 35kV busbar of the new energy station, the output side of the grid-connected switch 2 is connected to the input side of the isolating switch 4 through a cable passing through the zero-sequence current transformer 3, the output side of the isolating switch 4 is connected to the input side of the soft-start switch 5, the soft-start switch 5 is connected in parallel with the soft-start resistor 7, the output side of the soft-start switch 5 is connected to the input side of the air-core reactor 6, the output side of the air-core reactor 6 is connected to the incoming line of the SVG device body through the cable passing through the current Hall sensor 8, the secondary side of the zero-sequence current transformer 3 is connected to the input side of the isolating current transformer 9 through a sampling line, the output side of the isolating current transformer 9 is connected to the SVG controller of the SVG device body, the SVG controller is connected to the grid-connected switch 2, and the 35kV busbar of the new energy station is grounded through a resistor.

[0018] Embodiment 2

[0019] This embodiment is based on the first embodiment. In this embodiment, the 35kV busbar of the new energy station is connected to the power grid 1 through the step-up transformer output power, and the neutral point on the 35kV busbar line of the new energy station is grounded through a resistor;

[0020] In this embodiment, the current Hall sensor 8 and the isolation current transformer 9 are installed inside the SVG device body 10 , and the zero-sequence current transformer 3 is installed on the output side of the grid-connected switch 2 .

[0021] Embodiment 3

[0022] See also Figure 2 , Figure 2 This is a functional implementation circuit diagram of an SVG system with 35kV single-phase-to-ground protection function according to the utility model;

[0023] This embodiment is based on the first embodiment. In this embodiment, the SVG controller is connected to the tripping coil of the grid-connected switch through the intermediate relay KA. When a single-phase-to-ground fault occurs in the SVG system, the zero-sequence current transformer reaches the pre-configured protection threshold, the SVG controller detects the fault signal, acts on the intermediate relay KA, and the normally open contact of the relay closes to act on the tripping coil in the grid-connected switch, thereby cutting off the strong power of the SVG branch of the 35kV busbar of the new energy station, and the grid-connected switches of other branches of the 35kV busbar do not operate.

[0024] The SVG system with 35kV single-phase-to-ground protection function realizes single-phase-to-ground fault detection in the SVG system circuit. When a single-phase-to-ground fault occurs, it can quickly cut off the high-voltage power supply, effectively avoiding interlocking faults caused by single-phase-to-ground faults.

[0025] The preferred embodiments of the present application are described above with reference to the accompanying drawings, but the scope of the present application is not limited thereby. Any modification, equivalent substitution and improvement made by a person skilled in the art without departing from the scope and essence of the present application shall be within the scope of the present application.

Claims

1. An SVG system with 35kV single-phase-to-ground protection function, characterized in that: The invention comprises a grid-connected switch, a zero-sequence current transformer, an isolating switch, a soft-start switch, a soft-start resistor, an air-core reactor, a current Hall sensor and an SVG device body. The input side of the grid-connected switch is connected to the 35kV busbar of the new energy station. The output side of the grid-connected switch is connected to the input side of the isolating switch through a cable passing through the zero-sequence current transformer. The output side of the isolating switch is connected to the input side of the soft-start switch. The soft-start switch is connected in parallel with a soft-start resistor. The output side of the soft-start switch is connected to the input side of the air-core reactor. The output side of the air-core reactor is connected to the incoming line of the SVG device body through a cable passing through a current Hall sensor. The secondary side of the zero-sequence current transformer is connected to the input side of the isolating current transformer through a sampling line. The output side of the isolating current transformer is connected to the SVG controller of the SVG device body. The SVG controller is connected to the grid-connected switch. The 35kV busbar of the new energy station is grounded through a resistor.

2. The SVG system with 35kV single-phase-to-ground protection function according to claim 1 is characterized in that: The 35kV busbar of the new energy station is connected to the power grid through the step-up transformer to output electric energy, and the neutral point on the 35kV busbar line of the new energy station is grounded through a resistor.

3. The SVG system with 35kV single-phase-to-ground protection function according to claim 1, characterized in that: The SVG controller is connected to the opening coil of the grid-connected switch through an intermediate relay KA.

4. The SVG system with 35kV single-phase-to-ground protection function according to claim 2, characterized in that: The current Hall sensor and the isolation current transformer are installed inside the SVG device body, and the zero-sequence current transformer is installed on the output side of the grid-connected switch.

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