Optical storage electrical product grid-connected performance detection platform

Abstract

The utility model discloses a grid-connected performance detection platform for an optical storage electrical product. The grid-connected performance detection platform comprises a first direct-current power supply, a second direct-current power supply, an alternating-current power supply, an anti-islanding RLC load, a multi-channel data recorder, a direct-current wiring cabinet, an alternating-current wiring cabinet and an upper computer centralized control system, the alternating current power supply and the direct current power supply are both bidirectional programmable; the two direct-current power supplies can be used in parallel and can also be used independently; the alternating current power supply and the anti-islanding RLC load are connected to the alternating current wiring cabinet, and in the alternating current wiring cabinet, the wiring end of a to-be-tested product is connected with the anti-islanding RLC load and the alternating current power supply through a switch KM5 and a switch KM4 respectively. The photovoltaic grid-connected inverter and energy storage converter grid-connected performance detection platform is compatible with grid-connected performance detection of a photovoltaic grid-connected inverter and an energy storage converter, the utilization rate and economical efficiency of the platform are high, various standards can be met, and the number of grid-connected detection items is large.

Description

Technical Field

[0001] The utility model relates to a grid-connected performance testing platform for photovoltaic and energy storage electrical products in a laboratory, specifically a grid-connected performance testing platform for photovoltaic grid-connected inverters and energy storage converters based on power supply simulation. Background Art

[0002] Against the backdrop of the "dual carbon" goals, my country's photovoltaic installed capacity continues to achieve new breakthroughs, and power generation has steadily increased. Due to the randomness and volatility of photovoltaic power generation, the integration of photovoltaic power stations with energy storage is becoming a trend to improve grid stability.

[0003] As the penetration of photovoltaic power plants and energy storage power plants into the grid increases, their grid-connected performance directly impacts power quality and grid stability. PV power plants and energy storage power plants are connected to the grid via photovoltaic grid-connected inverters and energy storage converters, respectively. The grid-connected performance of these inverters and converters directly impacts the grid-connected performance of the power plants, making it particularly important to test the grid-connected performance of these inverters and converters.

[0004] Some of the grid-connected performance test items for inverters and converters are universal, such as active power control, primary frequency regulation, inertia response, reactive power control, power quality, voltage fault ride-through, grid adaptability, anti-islanding protection, and efficiency. In addition, energy storage converters have their own special items, such as charge and discharge switching time, voltage and current ripple. In addition, the photovoltaic grid-connected inverter converts the DC generated by the photovoltaic array into AC, while the energy storage converter can not only convert the DC of the energy storage battery into AC, but also rectify AC into DC to charge the energy storage battery. This application aims to design a platform for grid-connected performance testing of both photovoltaic grid-connected inverters and energy storage converters to improve the utilization and economy of the testing platform. Utility Model Content

[0005] The purpose of the utility model is to provide a platform for testing the grid-connected performance of both photovoltaic grid-connected inverters and energy storage converters, so as to improve the utilization rate and economy of the testing platform.

[0006] The purpose of the utility model is achieved through the following technical solutions: a grid-connected performance testing platform for photovoltaic storage electrical products, comprising a first DC power supply, a second DC power supply, an AC power supply, an anti-islanding RLC load, a multi-channel data recorder, a DC wiring cabinet, an AC wiring cabinet, and a host computer centralized control system;

[0007] The DC power supply is bidirectionally programmable and can simulate the IV curve output of photovoltaic array components as well as energy storage batteries;

[0008] The first DC power supply and the second DC power supply are both connected to the DC wiring cabinet. In the DC wiring cabinet, the first DC power supply and the second DC power supply are connected in parallel via a switch KM2 and are connected to the DC terminals DC1 and DC2 of the product under test via switches KM1 and KM3, respectively, so that the two DC power supplies can be used in parallel or separately.

[0009] The AC power supply is bidirectionally programmable and can simulate grid voltage amplitude and frequency changes, grid voltage superimposed harmonics, voltage fluctuations and flicker;

[0010] The anti-islanding RLC load consists of three parts: resistive load R, inductive load L and capacitive load C. The three phases are adjustable separately, and the resistive, capacitive and inductive loads are adjustable separately. Moreover, the active power of the resistive load, the reactive power of the inductive load and the reactive power of the capacitive load can meet the quality factor Q at 50Hz and 60Hz. f =1;

[0011] The AC power supply and the anti-islanding RLC load are both connected to the AC wiring cabinet. In the AC wiring cabinet, the terminal of the product under test is connected to the anti-islanding RLC load and the AC power supply through switches KM5 and KM4 respectively;

[0012] The multi-channel data recorder collects the voltage and current data at the DC terminals DC1 and DC2 of the DC wiring cabinet, as well as the voltage and current data on the product side to be tested, the grid side and the island load side of the AC wiring cabinet, and the control trigger signal of the switch KM4;

[0013] The host computer centralized control system is connected to the first DC power supply, the second DC power supply, the AC power supply, the anti-islanding RLC load, the DC wiring cabinet, the AC wiring cabinet, the multi-channel data recorder and the product to be tested, respectively, to control them and acquire data.

[0014] The utility model is compatible with the grid-connected performance detection of photovoltaic grid-connected inverters and energy storage converters. The platform has high utilization and economy, can meet multiple standards, and has many grid-connected detection items.

[0015] As a preferred embodiment, the anti-islanding RLC load is connected to the AC wiring cabinet via a transformer T1 with multiple adjustable gears, and the host computer centralized control system is connected to the transformer T1 to control its switching.

[0016] By adding a transformer at the anti-islanding RLC load, the testing platform can be compatible with the testing of products under test with a variety of rated AC output line voltages, making the platform more applicable.

[0017] The DC power supply can simulate various types of energy storage batteries.

[0018] The multi-channel data recorder also has a waveform display function, and can display the collected data in the form of waveforms.

[0019] Beneficial effects:

[0020] 1) The utility model detection platform is compatible with the grid-connected performance detection of photovoltaic grid-connected inverters and energy storage converters, and the platform has high utilization rate and economy;

[0021] 2) This new testing platform not only meets the new PV grid-connected inverter standards NB / T 32004-2018, GB / T 37408-2019, and GB / T 37409-2019, but is also compatible with the anti-islanding protection test in the Spanish grid-connected testing standard UNE 217002:2020;

[0022] 3) Grid-connected testing includes many items, not limited to power quality, anti-islanding protection, and grid adaptability, but also includes active power control, primary frequency regulation, inertia response, reactive power control, voltage fault ride-through, efficiency, charge-discharge switching time, voltage and current ripple, etc.

[0023] 4) Ability to accurately adjust grid-connected voltage and frequency;

[0024] 5) The utility model uses a feedback DC power supply that has both photovoltaic simulation and battery simulation, and the photovoltaic simulation and battery simulation can use the same circuit;

[0025] 6) The data logger collects voltage and current data on the inverter side, grid side, and island load side, and can accurately capture the current flowing from the grid to the anti-islanding load, which is more in line with standard requirements.

[0026] 7) The utility model detection platform is compatible with the testing of products under test with a variety of rated AC output line voltages and has a wide range of applications;

[0027] 8) This utility model adopts a host computer centralized control system to remotely control the operation of all equipment and collect data. It is easy to operate and is far away from high-voltage live areas, making it easy and safe to operate;

[0028] 9) Use a multi-channel data logger to replace the power analyzer and oscilloscope combination, reducing equipment usage. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a connection block diagram of the detection platform during testing of the preferred embodiment of the utility model;

[0030] Figure 2 yes Figure 1 Electrical wiring diagram of the DC junction cabinet;

[0031] Figure 3 yes Figure 1Electrical wiring diagram of the AC junction cabinet. DETAILED DESCRIPTION

[0032] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0033] The detection platform of this embodiment is compatible with the grid-connected performance detection of photovoltaic grid-connected inverters and energy storage converters, and includes a first DC power supply, a second DC power supply, an AC power supply, an anti-islanding RLC load, a multi-channel data recorder, a DC wiring cabinet, an AC wiring cabinet, a transformer T1, and a host computer centralized control system. The first DC power supply and the second DC power supply are both connected to the DC wiring cabinet, the AC power supply is connected to the AC wiring cabinet, and the anti-islanding RLC load is connected to the AC wiring cabinet through the transformer T1. The multi-channel data recorder is respectively connected to the DC wiring cabinet and the AC wiring cabinet to collect voltage and current data. The host computer centralized control system is respectively connected to the first DC power supply, the second DC power supply, the AC power supply, the anti-islanding RLC load, the DC wiring cabinet, the AC wiring cabinet, the transformer T1, and the multi-channel data recorder to control them and acquire data.

[0034] When testing, if Figure 1 As shown, the first DC power supply, the second DC power supply, and the AC power supply are all connected to the main power grid through a main power cabinet, also known as a distribution cabinet. The inverter / converter under test is connected to the DC wiring cabinet and / or AC wiring cabinet, and is also connected to the host computer centralized control system.

[0035] The DC power supply in this embodiment is bidirectional and programmable. It is controlled by the host computer centralized control system. It can simulate the IV curve output of photovoltaic array components and various types of energy storage batteries. The power can flow in both directions. In this design, two identical power supplies are used. They can be used in parallel or individually. This is achieved by controlling the DC wiring cabinet through the host computer centralized control system. Figure 2 As shown, the positive and negative poles of the first DC power supply are connected to the positive and negative ends of the DC terminal DC1 of the product under test via switch KM1, respectively. The positive and negative poles of the second DC power supply are connected to the positive and negative ends of the DC terminal DC2 of the product under test via switch KM3. Furthermore, the positive and negative poles of the first DC power supply are connected to the positive and negative poles of the second DC power supply via switch KM2, respectively. The multi-channel data recorder collects current and voltage data at DC terminals DC1 and DC2 through pre-set connection points in the DC wiring cabinet.

[0036] The AC power supply in this embodiment is bidirectionally programmable and can simulate the bidirectional power flow of a large power grid. Under the control of the host computer centralized control system, it can simulate the grid voltage amplitude and frequency changes, grid voltage superimposed harmonics, voltage fluctuations and flickers.

[0037] In this embodiment, the anti-islanding RLC load has a rated working line voltage of 400V / 50Hz and is compatible with 60Hz use. It consists of three parts: resistive load R, inductive load L, and capacitive load C. The three phases are adjustable separately, and the resistive, capacitive, and inductive loads are adjustable separately. It can be controlled and adjusted by the host computer centralized control system through the RS-485 bus. The active power design value of the resistive load matches the rated output active power of the AC power supply, and the active power of the resistive load, the reactive power of the inductive load, and the reactive power of the capacitive load can meet the quality factor Q at 50Hz and 60Hz. f = 1. The minimum standard power for resistive, inductive, and capacitive loads is 1W (VA), with a 1W (VA) step size. Load power is continuously adjustable. For anti-islanding RLC loads, we recommend the ACLT-681000T Anti-Islanding Test Device or the AC400V-1000kW-RLC Programmable RLC Load Simulator.

[0038] The above quality factor calculation formula is:

[0039]

[0040] Where:

[0041] P-resistive load active power;

[0042] Q1- inductive load reactive power;

[0043] Q C - Reactive power of capacitive loads.

[0044] like Figure 3 As shown in the figure, in the AC wiring cabinet, the terminal of the product under test is connected to the anti-islanding RLC load and the AC power supply through switches KM5 and KM4 respectively.

[0045] The multi-channel data recorder in this embodiment has 12 data acquisition channels, 11 of which can collect voltage data from 0-2000V and, in conjunction with an external current sensor, current data. The current sensor range must cover the maximum current of the line. The other channel is used to collect the control trigger signal of switch KM4. The multi-channel data recorder has a data sampling frequency of 2MHz and is connected to the host computer centralized control system via an RJ45 network port. The multi-channel data recorder selected in this embodiment combines post-data acquisition calculation and waveform display functions, displaying the collected data as a waveform.

[0046] like Figure 3 As shown, the multi-channel data recorder collects the voltage U on the side of the product under test in the AC wiring cabinet. EUT and current I EUT , grid-side voltage U AC and current I AC , the voltage U on the island load sideload and current I load , and the control trigger signal of switch KM4. Switch KM4 is connected to an external AC power source and is used to disconnect from the AC power source. When disconnected, it generates a trigger signal to the multi-channel data recorder for testing anti-islanding protection. Switch KM5 is connected to an external transformer T1 and is used to disconnect from transformer T1.

[0047] The connection group number of transformer T1 is YNd11, the primary rated working voltage (Y connection) is Ue=400V, the maximum working voltage is 1.1Ue, and the secondary voltage is adjustable in five levels: 315V, 400V, 480V, 690V, and 800V. It can adapt to anti-islanding protection tests of inverters / converters under test with AC output voltages of 315V, 400V, 480V, 690V, and 800V.

[0048] The host computer centralized control system includes an industrial computer host, display, router, and control software. It controls the operation and data transmission of the DC power supply, AC power supply, and multi-channel data recorder via network cables. It also controls the internal switches of the DC and AC wiring cabinets. It also controls the switching of transformer T1 and anti-islanding RLC load adjustment via RS485. The host computer centralized control system has CAN, RS-485, and Ethernet communication ports. Through these ports, it communicates with the inverter / converter under test, issues control information, and collects and displays communication data.

[0049] The host computer software has the following functions: 1) Optional 20ms, 200ms, and 1s period recording data to calculate effective values; 2) Analyze and measure harmonics, interharmonics, and high-frequency harmonics; 3) Measure voltage fluctuations and flicker; 4) Record AC port voltage and current with a step size of 1ms and a sliding window period of 20ms, and calculate the positive-sequence, negative-sequence, and zero-sequence components of voltage, current, active current, reactive current, active power, and reactive power; 5) Integrated oscilloscope function, which can be used for waveform display and analysis in the software.

[0050] In this embodiment, in addition to the anti-islanding protection test, during the test, the electric energy is transferred from the main power cabinet to the DC power supply, then to the inverter / converter to be tested, then to the AC source, and finally back to the main power cabinet, or the electric energy is reversely circulated, all of which can realize the internal circulation of electric energy. With the internal circulation of electric energy, the entire testing platform has low energy consumption and is green and environmentally friendly. The grid-connected performance test items of the inverter and converter that can be completed in this embodiment include active power control, primary frequency modulation, inertia response, reactive power control, power quality, voltage fault ride-through, grid adaptability, anti-islanding protection, efficiency, and the charge and discharge switching time, voltage and current ripple detection of the converter. Part of the detection process is as follows:

[0051] Inverter active power control

[0052] according to Figure 1 Connect the circuit, and connect the inverter DC input to DC1+ and DC1-. The host computer centralized control system controls KM1, KM2, and KM4 to close, and KM3 and KM5 to disconnect, controls the DC power supply to be used in parallel, and works in IV curve mode, and then controls the AC power supply to output the rated voltage and frequency of the product to be tested, and sets a multi-channel data recorder to collect the voltage U output of the inverter. EUT and current I EUT After the inverter is operating normally, the inverter output is controlled according to the inverter manufacturer's control method, decreasing from 100% Pn (rated output power) to 0% Pn in steps of 10% Pn, and then stepping back to 100% Pn. Each output power point is maintained for 2 minutes. The entire active power control process uses a multi-channel data recorder to collect inverter output data. The effective values ​​of the output voltage, current, frequency, active power, and power factor are calculated in a 200ms cycle. The control error and control response time are calculated based on the recorded actual output active power and the control target value.

[0053] Inverter Spanish standard UNE 217002:2020 anti-islanding protection

[0054] Two inverters of the same model, with the DC side of inverter 1 connected to DC1+ and DC1-, and the DC side of inverter 2 connected to DC2+ and DC2-. The outputs of the two inverters are connected in parallel to the AC wiring cabinet. The host computer centralized control system controls KM1, KM3, KM4, and KM5 to be closed and KM2 to be disconnected. The two DC power supplies are used separately, the secondary side voltage of transformer T1 is set to the rated voltage of the inverter, and a multi-channel data recorder is set to collect the inverter output voltage U EUT and current I EUT , grid side voltage U AC and current I AC , the voltage U on the island load side load and current I load , calculate the corresponding active power and reactive power. After setting the DC power supply and AC power supply so that the two inverters work as required, add an anti-islanding load resistive load to make the load active power P load Equal to the inverter output P EUT , then add inductive load to make the load Q load =P load , then add capacitive load to make Q load Approaching 0, the grid side current I AC The fundamental current is less than ±1% of the rated current of the inverter. After adjusting the above conditions, switch the data recorder to the waveform display interface to display the inverter output U EUT , I EUTThe waveform of the KM4 switch trigger signal is shown in Figure 1. The host computer centralized control system controls KM4 to disconnect. The cursor on the recorder waveform interface is used to measure the KM4 switch trigger signal to the inverter output I EUT The time it takes for the current to drop below 1% of the rated current is the anti-islanding protection time. This test is performed under two conditions: one with anti-islanding protection enabled on inverter 1 and disabled on inverter 2, and one with anti-islanding protection enabled on both inverters 1 and 2.

[0055] Voltage ripple and current ripple test of energy storage converter

[0056] according to Figure 1 Connect the circuit and connect the DC input of the converter to DC1+ and DC1-. The host computer centralized control system controls KM1, KM2, and KM4 to close and KM3 and KM5 to disconnect. Then it controls the AC power supply to output the rated voltage and frequency of the product under test, controls the DC power supply to be used in parallel and work in battery simulator mode, and sets a multi-channel data recorder to collect the converter input voltage U DC1 and current I DC1 Set the AC source to the rated voltage of the AC side of the converter, the DC side to the DC voltage to be measured, the converter works in the rated charging mode, and the data recorder records the DC side voltage U with a period of 200ms. DC1 and current I DC1 , calculate the AC components of the DC side voltage and current through the upper software, and then calculate the voltage ripple coefficient and current ripple coefficient.

[0057] The utility model detection platform has the following characteristics:

[0058] 1) The utility model detection platform is compatible with the grid-connected performance detection of photovoltaic grid-connected inverters and energy storage converters, and the platform has high utilization rate and economy;

[0059] 2) This new testing platform not only meets the new PV grid-connected inverter standards NB / T 32004-2018, GB / T 37408-2019, and GB / T 37409-2019, but is also compatible with the anti-islanding protection test in the Spanish grid-connected testing standard UNE 217002:2020;

[0060] 3) Grid-connected testing includes many items, not limited to power quality, anti-islanding protection, and grid adaptability, but also includes active power control, primary frequency regulation, inertia response, reactive power control, voltage fault ride-through, efficiency, charge-discharge switching time, voltage and current ripple, etc.

[0061] 4) Ability to accurately adjust grid-connected voltage and frequency;

[0062] 5) The utility model uses a feedback DC power supply that has both photovoltaic simulation and battery simulation, and the photovoltaic simulation and battery simulation can use the same circuit;

[0063] 6) The data logger collects voltage and current data on the inverter side, grid side, and island load side, and can accurately capture the current flowing from the grid to the anti-islanding load, which is more in line with standard requirements;

[0064] 7) The utility model detection platform is compatible with the testing of products under test with a variety of rated AC output line voltages and has a wide range of applications;

[0065] 8) This utility model adopts a host computer centralized control system to remotely control the operation of all equipment and collect data. It is easy to operate and is far away from high-voltage live areas, making it easy and safe to operate;

[0066] 9) Use a multi-channel data logger to replace the power analyzer and oscilloscope combination, reducing equipment usage.

Claims

1. A grid-connected performance testing platform for photovoltaic and electrical storage products, characterized in that: It includes a first DC power supply, a second DC power supply, an AC power supply, an anti-islanding RLC load, a multi-channel data recorder, a DC wiring cabinet, an AC wiring cabinet and a host computer centralized control system; The DC power supply is bidirectionally programmable and can simulate the IV curve output of photovoltaic array components as well as energy storage batteries; The first DC power supply and the second DC power supply are both connected to the DC wiring cabinet. In the DC wiring cabinet, the first DC power supply and the second DC power supply are connected in parallel via a switch KM2 and are connected to the DC terminals DC1 and DC2 of the product under test via switches KM1 and KM3, respectively. The AC power supply is bidirectionally programmable and can simulate grid voltage amplitude and frequency changes, grid voltage superimposed harmonics, voltage fluctuations and flicker; The anti-islanding RLC load consists of three parts: resistive load R, inductive load L and capacitive load C. The three phases are adjustable separately, and the resistive, capacitive and inductive loads are adjustable separately. Moreover, the active power of the resistive load, the reactive power of the inductive load and the reactive power of the capacitive load can meet the quality factor Q at 50Hz and 60Hz. f =1; The AC power supply and the anti-islanding RLC load are both connected to the AC wiring cabinet. In the AC wiring cabinet, the terminal of the product under test is connected to the anti-islanding RLC load and the AC power supply through switches KM5 and KM4 respectively; The multi-channel data recorder collects the voltage and current data at the DC terminals DC1 and DC2 of the DC wiring cabinet, as well as the voltage and current data on the product side to be tested, the grid side and the island load side of the AC wiring cabinet, and the control trigger signal of the switch KM4; The host computer centralized control system is connected to the first DC power supply, the second DC power supply, the AC power supply, the anti-islanding RLC load, the DC wiring cabinet, the AC wiring cabinet, the multi-channel data recorder and the product to be tested, respectively, to control them and acquire data.

2. The detection platform according to claim 1, characterized in that: The anti-islanding RLC load is connected to the AC wiring cabinet via a transformer T1 with multiple adjustable gears. The host computer centralized control system is connected to the transformer T1 to control its switching.

3. The detection platform according to claim 1, characterized in that: The DC power supply is a DC power supply that can simulate various types of energy storage batteries.

4. The detection platform according to claim 1, characterized in that: The multi-channel data recorder is a recorder with a waveform display function, which can display the collected data in the form of waveforms.

Images