Distributed oscillation monitoring and positioning device for photovoltaic power station

Abstract

A distributed oscillation monitoring and positioning device for a photovoltaic power station comprises an in-station monitoring and positioning device and a distributed monitoring and positioning device. A voltage and current module of the in-station monitoring and positioning device is electrically connected with an AD conversion circuit I. A microprocessor I is electrically connected with the AD conversion circuit I and a 4G receiver. The low-voltage side of a measuring box type boosting transformer of the distributed monitoring and positioning device is electrically connected with an AD conversion circuit II, and a microprocessor II is electrically connected with the AD conversion circuit II and a 4G transmitter; and the 4G receiver is electrically connected with the 4G transmitter. Oscillation of a new energy station can be automatically monitored, and a specific oscillation current collection line, a reactive power compensation device and even an oscillation inverter area can be positioned. Information such as oscillation alarm information, oscillation frequency, an oscillation current collection line, a reactive power compensation device and an inverter area can be sent out; operation is simple, and use is convenient.

Description

Technical Field

[0001] The utility model belongs to the technical field of photovoltaic power stations and relates to a distributed oscillation monitoring and positioning device for a photovoltaic power station. Background Art

[0002] With the construction of new power systems and the large-scale integration of renewable energy sources into the grid, there have been numerous cases of oscillations caused by renewable energy stations. These oscillations can also be caused by faults in the station's collector lines or reactive power compensation devices. These oscillations can last for tens of minutes and can even cause oscillations in DC transmission lines, 500kV lines, and hydro-thermal generators. Furthermore, renewable energy station operations and maintenance personnel often fail to immediately detect these oscillations, leading to grid active power oscillations that are then discovered and manually assessed by grid dispatchers. These personnel then alert the renewable energy stations and initiate suppression measures. These stations often fail to promptly identify active power oscillations, posing a threat to grid security and stability.

[0003] Standards such as GB 38755 "Guidelines for Power System Security and Stability," GB / T 40594-2021 "Technical Guidelines for Power System Grid-Source Coordination," GB / T 19964-2024 "Technical Provisions for the Integration of Photovoltaic Power Stations into Power Systems," and GB / T 19963.1-2021 "Technical Provisions for the Integration of Wind Farms into Power Systems (Part 1: Onshore Wind Power)" explicitly require monitoring measures for renewable energy sites posing oscillation risks. With the large-scale and high-proportion integration of renewable energy, ensuring the safe and stable operation of power grids in the presence of active power oscillations at these sites is a crucial issue. Summary of the Invention

[0004] The technical problem to be solved by the utility model is to provide a distributed oscillation monitoring and positioning device for photovoltaic power stations, which adjusts the voltage through a feedback control module to solve the problem of no photovoltaic power station oscillation monitoring and positioning device, and to make up for the shortcomings of existing photovoltaic power station oscillation monitoring and positioning equipment.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a distributed oscillation monitoring and positioning device for a photovoltaic power station, which includes an in-station monitoring and positioning device and a distributed monitoring and positioning device; the voltage and current module of the in-station monitoring and positioning device is electrically connected to the AD conversion circuit I, and the microprocessor I is electrically connected to the AD conversion circuit I and the 4G receiver; the low-voltage side of the measuring box-type step-up transformer of the distributed monitoring and positioning device is electrically connected to the AD conversion circuit II, and the microprocessor II is electrically connected to the AD conversion circuit II and the 4G transmitter; the 4G receiver and the 4G transmitter are electrically connected.

[0006] The voltage and current modules of the internal monitoring and positioning device include a module for measuring the voltage and current of the photovoltaic power station grid connection point, a module for measuring the voltage and current of the collector line, and a module for measuring the voltage and current of the reactive compensation device.

[0007] The microprocessor 1 is also electrically connected to the display module, the storage module and the key module.

[0008] The voltage and current module includes three-phase voltage and current measurement channels A, B, and C, wherein each three-phase voltage and current module includes three voltage transformers PTA, PTB, and PTC, and three current transformers CTA, CTB, and CTC; the three voltage transformers PTA, PTB, and PTC, and the three current transformers CTA, CTB, and CTC are respectively connected to the I / O ports of the AD conversion chip.

[0009] The module for measuring the voltage and current of the collector line and the module for measuring the voltage and current of the reactive compensation device can measure up to 10 three-phase voltage and current signals.

[0010] The main beneficial effects of the utility model are:

[0011] It can not only automatically monitor the oscillation of new energy stations, but also locate specific oscillating collection lines, reactive compensation devices, and even oscillating inverter areas; it can issue oscillation alarm information, oscillation frequency, oscillation collection lines, reactive compensation devices, inverter areas and other information.

[0012] Automatic monitoring is possible. It can automatically monitor the grid connection point transmission line, collection line, reactive power compensation device output, inverter area and other circuit information.

[0013] It is easy to operate and use. It can be widely used in wind farms, energy storage power stations, "wind, solar and storage" combined power stations, distributed new energy and other occasions. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0015] Figure 1 This is a structural diagram of the in-station monitoring and positioning device of the present utility model.

[0016] Figure 2 This is a schematic structural diagram of the distributed monitoring and positioning device of the present utility model.

[0017] Figure 3 This is a schematic diagram of the three-phase voltage and current measurement of the utility model.

[0018] Figure 4 This is a schematic diagram of the A-phase voltage and current measurement of the utility model.

[0019] Markings in the figure: 1 is microprocessor I, 2 is module for measuring voltage and current of photovoltaic power station grid connection point, 3 is module for measuring voltage and current of collector line, 4 is module for measuring voltage and current of reactive compensation device, 5 is AD conversion circuit I, 6 is display module, 7 is storage module, 8 is key module, 9 is 4G receiver, 10 is 4G transmitter, 11 is microprocessor II, 12 is AD conversion circuit II, 13 is module for measuring voltage and current of low-voltage side of box-type step-up transformer.

[0020] The letters in the figure are: PTA, PTB, PTC represent voltage transformers; CTA, CTB, CTC represent current transformers; R1, R2 are fixed value resistors. DETAILED DESCRIPTION

[0021] like Figures 1 to 4 A distributed oscillation monitoring and positioning device for a photovoltaic power station is disclosed, comprising an in-station monitoring and positioning device and a distributed monitoring and positioning device; the voltage and current module of the in-station monitoring and positioning device is electrically connected to an AD conversion circuit I, and a microprocessor I is electrically connected to the AD conversion circuit I and a 4G receiver; the low-voltage side of a measuring box-type step-up transformer of the distributed monitoring and positioning device is electrically connected to an AD conversion circuit II, and the microprocessor II is electrically connected to the AD conversion circuit II and a 4G transmitter; and the 4G receiver is electrically connected to the 4G transmitter.

[0022] Preferably, the voltage and current of the photovoltaic power station grid connection point, the voltage and current of the collector line, and the voltage and current of the reactive compensation device outlet line are measured, and the analog quantity is converted into a digital quantity and input into the microprocessor I through the AD conversion circuit I. The microprocessor I is connected to the storage module, the key module, the display module, and the 4G receiver; the voltage and current on the low-voltage side of the box-type transformer are measured, and the analog quantity is converted into a digital quantity and input into the microprocessor II through the AD conversion circuit II. The microprocessor I is connected to the 4G transmitter.

[0023] Preferably, microprocessor I and microprocessor II are existing conventional processors.

[0024] Preferably, the microprocessor 1 uses the full-wave Fourier method to calculate the fundamental positive-sequence voltage, fundamental positive-sequence active power, and fundamental positive-sequence reactive power of the photovoltaic power station grid connection point, calculates the fundamental positive-sequence voltage, fundamental positive-sequence active power, and fundamental positive-sequence reactive power of the collector line, and calculates the fundamental positive-sequence voltage and fundamental positive-sequence reactive power output by the reactive compensation device.

[0025] Microprocessor II uses the full-wave Fourier method to calculate the fundamental positive sequence voltage, fundamental positive sequence active power and fundamental positive sequence reactive power on the low voltage side of the photovoltaic array box transformer.

[0026] Microprocessor I determines whether the fundamental positive sequence voltage, fundamental positive sequence active power, and fundamental positive sequence reactive power of the photovoltaic power station grid connection point and the collector line have oscillations; microprocessor II determines whether the fundamental positive sequence voltage, fundamental positive sequence active power, and fundamental positive sequence reactive power of the photovoltaic array have oscillations.

[0027] Preferably, the 4G receiver and the 4G transmitter adopt existing conventional 4G receivers and 4G transmitters; one 4G receiver can receive signals and data from multiple 4G transmitters.

[0028] In a preferred solution, the voltage and current modules of the internal monitoring and positioning device include a module for measuring the voltage and current of the photovoltaic power station grid connection point, a module for measuring the voltage and current of the collector line, and a module for measuring the voltage and current of the reactive compensation device.

[0029] In a preferred embodiment, the microprocessor 1 is also electrically connected to the display module, the storage module and the key module.

[0030] In a preferred solution, the voltage and current module includes three-phase voltage and current measurement channels A, B, and C, wherein each three-phase voltage and current module includes three voltage transformers PTA, PTB, and PTC, and three current transformers CTA, CTB, and CTC; the three voltage transformers PTA, PTB, and PTC, and the three current transformers CTA, CTB, and CTC are respectively connected to the I / O port of the AD conversion chip.

[0031] Preferably, the AD conversion circuits I and II mainly include an AD conversion chip and its auxiliary circuits, and the AD conversion chip adopts an existing conventional AD conversion chip.

[0032] Preferably, taking the voltage and current measurement of phase A as an example, one end of the primary side of the voltage transformer PTA is connected to the phase A loop, the other end of the primary side of the voltage transformer PTA is grounded, a resistor R1 is connected in parallel to the secondary side of the voltage transformer PTA, one end of the secondary side of the voltage transformer PTA is connected to the Vin port of the AD conversion chip, and the other end of the secondary side of the voltage transformer PTA is grounded; the primary side of the current transformer CTA is connected in series to the phase A loop, a resistor R2 is connected in parallel to the secondary side of the current transformer CTA, one end of the secondary side of the current transformer CTA is connected to the Iin port of the AD conversion chip, and the other end of the secondary side of the current transformer CTA is grounded.

[0033] In a preferred solution, the module for measuring the voltage and current of the collector line and the module for measuring the voltage and current of the reactive compensation device can measure up to 10 three-phase voltage and current signals.

[0034] Preferably, multiple distributed monitoring and positioning devices can be installed on each collector line in a photovoltaic power station and installed on the low-voltage side of the box-type transformer.

[0035] Example 1,

[0036] During use, the photovoltaic power station is equipped with an in-station monitoring and positioning device, and multiple sets of distributed monitoring and positioning devices are installed on each collector line; and the transformation ratio of the sampled voltage and current is set through the key module 8.

[0037] Measuring the voltage and current of the photovoltaic power station grid connection point 2 monitors the voltage and current of the grid connection point in real time. The microprocessor I1 calculates the fundamental positive sequence voltage, fundamental positive sequence active power, and fundamental positive sequence reactive power of the grid connection point through the full-wave Fourier algorithm. The microprocessor I1 determines whether the fundamental positive sequence voltage, fundamental positive sequence active power, and fundamental positive sequence reactive power of the photovoltaic power station grid connection point have oscillations.

[0038] If there is no oscillation at the grid connection point, it will continue to be in the monitoring state.

[0039] If there is oscillation at the grid connection point, the microprocessor I1 calculates the fundamental positive-sequence voltage, fundamental positive-sequence active power, fundamental positive-sequence reactive power of the collector line, and the fundamental positive-sequence voltage and fundamental positive-sequence reactive power output by the reactive compensation device through the full-wave Fourier algorithm; the microprocessor I1 further determines which line, the collector line or the reactive compensation device output line, has oscillation.

[0040] If the fundamental positive sequence voltage or fundamental positive sequence reactive power output by the reactive compensation device oscillates, the microprocessor I1 outputs the reactive compensation device output oscillation through the display module 6 and stores the data and oscillation information in the storage module 7 .

[0041] If the fundamental positive-sequence voltage, fundamental positive-sequence active power, and fundamental positive-sequence reactive power of the collector line oscillate, the oscillating collector line is output and the data and oscillation information are stored in the storage module 7. The distributed monitoring and positioning device for the oscillating collector line reads data via the 4G receiver 9. The low-voltage side voltage and current 13 of the box-type transformer are measured and converted by the AD conversion circuit II 12. The microprocessor II 11 transmits the data to the 4G receiver 9 via the 4G transmitter 10. The microprocessor I1 determines which inverter area is oscillating and outputs the oscillation information on the display module 6. Oscillation monitoring and positioning are completed.

[0042] It not only automatically monitors oscillations at new energy stations but also locates specific oscillating collector lines, reactive power compensation devices, and even oscillating inverter areas. It can also issue oscillation alarms, oscillation frequency, oscillating collector lines, reactive power compensation devices, inverter areas, and other information. This enables automated monitoring. It can automatically monitor information on the grid connection point's outgoing lines, collector lines, reactive power compensation device output, inverter areas, and other circuits.

[0043] The above embodiments are merely preferred technical solutions of the present invention and should not be construed as limiting the present invention. The embodiments and features therein may be arbitrarily combined unless they conflict. The scope of protection of the present invention shall be the technical solutions described in the claims, including equivalent alternatives to the technical features of the technical solutions described in the claims. Equivalent alternatives and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A distributed oscillation monitoring and positioning device for a photovoltaic power station, characterized by: It includes an in-station monitoring and positioning device and a distributed monitoring and positioning device; the voltage and current module of the in-station monitoring and positioning device is electrically connected to the AD conversion circuit I, and the microprocessor I is electrically connected to the AD conversion circuit I and the 4G receiver; the low-voltage side of the measuring box-type step-up transformer of the distributed monitoring and positioning device is electrically connected to the AD conversion circuit II, and the microprocessor II is electrically connected to the AD conversion circuit II and the 4G transmitter; the 4G receiver and the 4G transmitter are electrically connected.

2. The photovoltaic power station distributed oscillation monitoring and positioning device according to claim 1, characterized in that: The voltage and current modules of the internal monitoring and positioning device include a module for measuring the voltage and current of the photovoltaic power station grid connection point, a module for measuring the voltage and current of the collector line, and a module for measuring the voltage and current of the reactive compensation device.

3. The photovoltaic power station distributed oscillation monitoring and positioning device according to claim 1, characterized in that: The microprocessor 1 is also electrically connected to the display module, the storage module and the key module.

4. The photovoltaic power station distributed oscillation monitoring and positioning device according to claim 1, characterized in that: The voltage and current module includes three-phase voltage and current measurement channels A, B, and C, wherein each three-phase voltage and current module includes three voltage transformers PTA, PTB, and PTC, and three current transformers CTA, CTB, and CTC; the three voltage transformers PTA, PTB, and PTC, and the three current transformers CTA, CTB, and CTC are respectively connected to the I / O ports of the AD conversion chip.

5. The photovoltaic power station distributed oscillation monitoring and positioning device according to claim 2, characterized in that: The module for measuring the voltage and current of the collector line and the module for measuring the voltage and current of the reactive compensation device can measure up to 10 three-phase voltage and current signals.

Images