Current collection line energy-saving system

Abstract

The utility model relates to the technical field of photovoltaic power stations, and provides a current collection line energy-saving system, which comprises a grid-connected high-voltage circuit breaker, the grid-connected high-voltage circuit breaker is connected with one end of an isolating switch, and the other end of the isolating switch is respectively connected with a first end of a main loop contactor, a first end of a bypass contactor and one end of a PT fuse. The second end of the main loop contactor is connected with one end of the resistor, the other end of the resistor is connected with the first end of the second current transformer, the second end of the second current transformer is connected with the second end of the bypass contactor and the first end of the first current transformer, and the second end of the first current transformer is grounded. The other end of the PT fuse is connected with one end of the voltage transformer, the other end of the voltage transformer is connected with the third end of the main loop contactor, the third end of the bypass contactor and one end of the controller, and the other end of the controller is connected with the third end of the second current transformer and the third end of the first current transformer.

Description

Technical Field

[0001] The utility model is designed in the technical field of photovoltaic power stations, and in particular relates to a collector line energy-saving system. Background Art

[0002] The statements in this section merely provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] In the photovoltaic grid-connected power generation system, the photovoltaic box transformer is one of the key equipment, and its operating efficiency has received widespread attention, because increasing the efficiency by 2‰ will also bring significant economic benefits. One of the biggest features of the photovoltaic box transformer is that it is completely in a no-load operation state at night. At this time, the power grid is equivalent to the power supply of the transformer, and the transformer absorbs the power of the power grid. Taking a 1MW photovoltaic grid-connected power generation system as an example, a 35kV transformer with a capacity of 1000KVA is configured, and its no-load loss is about 2000W, and the annual power consumption is about 9125 degrees. On the other hand, the current photovoltaic power station uses a large number of solid insulated cables with large capacity. When the box transformer is running at no load at night, the system is prone to no-load harmonics and resonant overvoltage, which leads to explosion of lightning arresters, explosion of cable heads, and burning of PTs on site. It not only brings huge economic losses to the enterprise, but also seriously affects the normal power generation of the system.

[0004] In summary, due to the limitations of the current design specifications of photovoltaic power stations and the characteristics of the distribution equipment they are equipped with, it is impossible to achieve frequent start and stop operations of the collection lines every day, resulting in long-term no-load losses in the power station. Utility Model Content

[0005] In order to solve the technical problems existing in the above-mentioned background technology, the utility model provides a collector line energy-saving system.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A first aspect of the utility model provides a collector line energy-saving system.

[0008] A collector line energy-saving system comprises: a grid-connected high-voltage circuit breaker, wherein the grid-connected high-voltage circuit breaker is connected to one end of an isolating switch, the other end of the isolating switch is respectively connected to the first end of a main circuit contactor, the first end of a bypass contactor and one end of a PT fuse, the second end of the main circuit contactor is connected to one end of a resistor, the other end of the resistor is connected to the first end of a second current transformer, the second end of the second current transformer is respectively connected to the second end of the bypass contactor and the first end of the first current transformer, the second end of the first current transformer is grounded, the other end of the PT fuse is connected to one end of a voltage transformer, the other end of the voltage transformer is respectively connected to the third end of the main circuit contactor, the third end of the bypass contactor and one end of a controller, and the other end of the controller is respectively connected to the third end of the second current transformer and the third end of the first current transformer.

[0009] Furthermore, the collector line energy-saving system is connected in series between the high-voltage switch cabinet and the photovoltaic step-up transformer.

[0010] Furthermore, the main circuit contactor adopts JCZ9-40.5 / 400A series.

[0011] Furthermore, the first current transformer adopts LZZBJ9-35 300 / 5 0.5 / 5P20 series.

[0012] Furthermore, the second current transformer adopts LZZBJ9-35 300 / 5 0.5 / 5P20 series.

[0013] Furthermore, the voltage transformer adopts JDZX-35 / 0.1 / 0.22.

[0014] Furthermore, the bypass contactor adopts JN27-40.5 / 630A series.

[0015] Furthermore, the isolating switch adopts JN27-40.5 / 630A series.

[0016] Furthermore, the resistor is GZN-35KV / 1600W-250.

[0017] Furthermore, the controller is connected to a switch status comprehensive display via a cable, and the switch status comprehensive display adopts NY900 series.

[0018] Compared with the prior art, the beneficial effects of the utility model are:

[0019] The utility model sets a bypass contactor to cut off the collector line system, which does not affect the normal operation of the photovoltaic transmission line system under any circumstances. When the main circuit contactor and the bypass contactor are cut off, the entire photovoltaic transmission line system will stop running. When there is sufficient sunlight during the day, the bypass contactor is opened, the main circuit contactor is closed, and the photovoltaic collector line generates electricity normally; when there is insufficient sunlight at night, the bypass contactor is opened, the main circuit contactor is opened, the photovoltaic collector line is disconnected, and the collector line no longer consumes electricity, saving electricity. When a system fails, the bypass contactor is closed to ensure the normal operation of photovoltaic power generation. For systems without photovoltaic collector lines, when photovoltaic power generation is not performed at night, the line will not be disconnected, and there will still be power consumption in the power station line. That is, the utility model can effectively solve the loss of the collector line during normal operation by designing the main circuit contactor and the bypass contactor, and the use of fast and high-power contactors can meet the requirements of frequent startup. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0021] Figure 1 It is a structural diagram of the energy-saving system of the power collection line shown in the utility model;

[0022] Figure 2 This is a schematic diagram of a power supply circuit of an AC220V AC small busbar supplying power to equipment in a cabinet;

[0023] Figure 3 This is a secondary control circuit diagram of high-voltage electrical equipment in an energy-saving cabinet shown in the utility model;

[0024] Among them, G1, isolating switch, DL1, main circuit contactor, DL2, bypass contactor, R2, PT fuse, PT1, voltage transformer, KZQ, controller, R1, resistor, CT2, second current transformer, CT1, first current transformer. DETAILED DESCRIPTION

[0025] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0026] It should be noted that the following detailed descriptions are all exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0027] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the utility model. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0028] Embodiment 1

[0029] like Figure 1 As shown, a collector line energy-saving system includes: a grid-connected high-voltage circuit breaker, wherein the grid-connected high-voltage circuit breaker is connected to one end of an isolating switch G1, the other end of the isolating switch G1 is respectively connected to the first end of a main circuit contactor DL1, the first end of a bypass contactor DL2 and one end of a PT fuse R2, the second end of the main circuit contactor DL1 is connected to one end of a resistor R1, the other end of the resistor R1 is connected to the first end of a second current transformer CT2, the second end of the second current transformer CT2 is respectively connected to the second end of the bypass contactor DL2 and the first end of the first current transformer CT1, the second end of the first current transformer CT1 is grounded, the other end of the PT fuse R2 is connected to one end of a voltage transformer PT1, the other end of the voltage transformer PT1 is respectively connected to the third end of the main circuit contactor DL1, the third end of the bypass contactor DL2 and one end of a controller KZQ, and the other end of the controller KZQ is respectively connected to the third end of the second current transformer CT2 and the third end of the first current transformer CT1.

[0030] The collector line energy-saving system is connected in series between the high-voltage switch cabinet and the photovoltaic step-up transformer.

[0031] The main circuit contactor DL1 adopts JCZ9-40.5 / 400A series, the first current transformer CT1 adopts LZZBJ9-35 300 / 5 0.5 / 5P20 series, the second current transformer CT2 adopts LZZBJ9-35 300 / 5 0.5 / 5P20 series, the voltage transformer PT1 adopts JDZX-35 / 0.1 / 0.22, the bypass contactor DL2 adopts JN27-40.5 / 630A series, the isolating switch G1 adopts JN27-40.5 / 630A series, the resistor R1 adopts GZN-35KV / 1600W-250, and the controller is connected to the switch status comprehensive display via a cable, and the switch status comprehensive display adopts NY900 series.

[0032] Among them, the basic technical parameters of high-voltage switchgear include: rated voltage: 40.5kV; rated frequency: 50HZ; one-minute power frequency withstand voltage: 95kV between phases and relative to ground, 115kV for isolation; lightning impulse withstand voltage: 185kV between phases and relative to ground; isolation break 215kV; rated current: 630A; rated thermal stability current: 31.5kA / 4S; rated short-circuit breaking current: 31.5kA; rated dynamic stability current: 63kA; rated short-circuit closing current: 63kA;

[0033] 35kV contactor parameters, including: Model: JCZ9-40.5 / 400A; Pole type: air insulation with permanent magnet mechanism; Rated voltage: 40.5kV; Rated current: 630A; Rated frequency: 50HZ; Main circuit closing capacity (A / 100 times): 6300A; Main circuit breaking capacity (A / 25 times): 5000A; Extreme segmentation capacity (A / 3 times): 6300A; Electrical life (10,000 times): 300,000; Mechanical life (10,000 times): 100,000; Main circuit power frequency withstand voltage (break): 85kV; Phase-phase, phase-ground power frequency withstand voltage: 95kV; Lightning impulse withstand voltage: 185kV; Control circuit power frequency withstand voltage: 2kV; Contact opening distance (mm): 17±2; Overtravel (mm): 3±1; Main circuit contact resistance: ≤200μΩ; Secondary control voltage: AC220V or DC220V.

[0034] The switch state analog display instrument includes: use environment: -20-65℃, ≤95%RH; dielectric strength: ≥AC2000V between the shell and the segment; insulation performance: ≥100MΩ between the shell and the segment.

[0035] The collector line energy-saving system is directly connected in series between the high-voltage switchgear and the photovoltaic step-up transformer, which does not affect the power transmission function of the original circuit and does not affect the relay protection function of the original circuit.

[0036] The system is mainly equipped with a main on-off circuit for frequent operations and a bypass circuit for maintaining normal operation of the system; the system is designed with a special suppression circuit for collector line overvoltage and excitation inrush current; the system is designed with a fuse development circuit to automatically achieve electrical interlocking.

[0037] Among them, the main circuit contactor DL1 is the main on-off circuit. The main circuit contactor DL1 and the bypass contactor DL2 are not allowed to be closed at the same time. The main circuit contactor DL1 and the bypass contactor DL2 are interlocked with each other. When the main circuit contactor DL1 works, the bypass contactor DL2 should be opened. When the main circuit contactor DL1 is closed, the main circuit works. When the main circuit contactor DL1 is opened, the main circuit is disconnected. When the energy-saving cabinet participates in the system operation, the bypass contactor DL2 switch is opened and the main circuit contactor DL1 works.

[0038] The bypass contactor DL2 is a bypass circuit. The main circuit contactor DL1 and the bypass contactor DL2 are not allowed to be closed at the same time. The main circuit contactor DL1 and the bypass contactor DL2 are interlocked with each other. When the bypass contactor DL2 is closed, the main circuit contactor DL1 is opened, the bypass circuit works, the bypass contactor DL2 is opened, and the bypass circuit is opened. When this collector line energy-saving system does not participate in the system operation, the bypass contactor DL2 is closed, the main circuit contactor DL1 is opened, and the energy-saving cabinet system is isolated.

[0039] R1 is a special suppression circuit resistor. By connecting resistor R1 in the main circuit, the excitation current generated by the switching of the transformer can be eliminated.

[0040] R2 is the PT fuse development circuit. If there is a large fault current in the system, the PT will fuse and the protection system will be activated. Due to the blowing of the fuse, the low voltage protection of the system may trip, or the fuse of the voltage transformer may blow, causing the protection system to send a grounding alarm signal and the switch protection to trip, thereby protecting the system equipment.

[0041] A contactor is a widely used switching device that uses electromagnetic, pneumatic or hydraulic principles to control the main circuit. When the contactor coil is energized, the coil current will generate a magnetic field. The generated magnetic field causes the static iron core to generate electromagnetic attraction to attract the moving iron core, and drives the AC contactor to move. The normally closed contact opens and the normally open contact closes. The two are linked. When the coil is de-energized, the electromagnetic attraction disappears, and the armature is released under the action of the release spring, so that the contacts are restored, the normally open contact opens, and the normally closed contact closes.

[0042] like Figure 2 As shown, the collector line energy-saving system also includes a temperature and humidity sensor, a small busbar for providing power for an air switch, instrument room lighting, cable room lighting, a thermostat, a cable room heater, and a display device.

[0043] Figure 3 It is the secondary control circuit of the high-voltage electrical equipment in the collector line energy-saving system, and controls the opening and closing signals of the main circuit contactor DL1 and the bypass contactor DL2. When the control knob is turned to the remote position, the main circuit contactor DL1 and the bypass contactor DL2 are remotely controlled by the controller to open and close. The control process of the controller does not belong to the protection scope of the present utility model, and is implemented by the existing technology. When the control knob is turned to the local position, the main circuit contactor DL1 and the bypass contactor DL2 are manually opened and closed by the control button in front of the cabinet, and the corresponding control status signal is displayed on the local panel. At the same time, when an electrical fault occurs in the system, the controller sends a control signal, and the corresponding main circuit contactor DL1 and the bypass contactor DL2 will trip accordingly to protect the system circuit. The main circuit contactor DL1 and the bypass contactor DL2 are interlocked with each other, and the main circuit contactor DL1 and the bypass contactor DL2 are not allowed to be closed at the same time.

[0044] The collector line energy-saving system is equipped with 1 incoming line and 1 outgoing line. The secondary circuit control power supply of the system adopts the main circuit PT transformer for power supply, and no secondary power supply is required.

[0045] The equipment is simple and convenient to install, and can meet the needs of rapid installation, rapid commissioning and rapid delivery, with little impact on the power generation of the photovoltaic power station.

[0046] In summary, the collector line energy-saving system can be stably, reliably and safely applied to the collector line system of photovoltaic power stations, realize automatic dynamic management of the collector circuit and large-capacity photovoltaic step-up transformer, reduce various standby losses, and is an important energy-saving means to reduce self-use electricity loss.

[0047] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A collector line energy-saving system, characterized in that: include: A grid-connected high-voltage circuit breaker, wherein the grid-connected high-voltage circuit breaker is connected to one end of the isolating switch, the other end of the isolating switch is respectively connected to the first end of the main circuit contactor, the first end of the bypass contactor and one end of the PT fuse, the second end of the main circuit contactor is connected to one end of the resistor, the other end of the resistor is connected to the first end of the second current transformer, the second end of the second current transformer is respectively connected to the second end of the bypass contactor and the first end of the first current transformer, the second end of the first current transformer is grounded, the other end of the PT fuse is connected to one end of the voltage transformer, the other end of the voltage transformer is respectively connected to the third end of the main circuit contactor, the third end of the bypass contactor and one end of the controller, and the other end of the controller is respectively connected to the third end of the second current transformer and the third end of the first current transformer.

2. The collector line energy-saving system according to claim 1, characterized in that: The collector line energy-saving system is connected in series between the high-voltage switch cabinet and the photovoltaic step-up transformer.

3. The collector line energy-saving system according to claim 1, characterized in that: The main circuit contactor adopts JCZ9-40.5 / 400A series.

4. The collector line energy-saving system according to claim 1, characterized in that: The first current transformer adopts LZZBJ9-35 300 / 5 0.5 / 5P20 series.

5. The collector line energy-saving system according to claim 1, characterized in that: The second current transformer adopts LZZBJ9-35 300 / 5 0.5 / 5P20 series.

6. The collector line energy-saving system according to claim 1, characterized in that: The voltage transformer adopts JDZX-35 / 0.1 / 0.

22.

7. The collector line energy saving system according to claim 1, characterized in that: The bypass contactor adopts JN27-40.5 / 630A series.

8. The collector line energy-saving system according to claim 1, characterized in that: The isolating switch is of JN27-40.5 / 630A series.

9. The collector line energy-saving system according to claim 1, characterized in that: The resistor is GZN-35KV / 1600W-250.

10. The collector line energy-saving system according to claim 1, characterized in that: The controller is connected to a switch status comprehensive display instrument via a cable, and the switch status comprehensive display instrument adopts NY900 series.

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