CN114859241A

CN114859241A - Intelligent microgrid energy storage system test method based on micro synchronous phasor measurement

Info

Publication number: CN114859241A
Application number: CN202210264713.3A
Authority: CN
Inventors: 魏新迟; 时珊珊; 方陈; 白纪军; 柳劲松; 刘舒
Original assignee: State Grid Shanghai Electric Power Co Ltd
Current assignee: State Grid Shanghai Electric Power Co Ltd
Priority date: 2022-03-17
Filing date: 2022-03-17
Publication date: 2022-08-05

Abstract

The invention relates to a micro-grid energy storage system testing method based on micro synchronous phasor measurement, wherein an intelligent micro-grid comprises an energy storage system, an energy storage performance testing system and auxiliary electricity consumption measuring equipment, the energy storage system comprises an energy storage battery pack and operation control equipment, the operation control equipment is connected into a grid through a three-phase line, the energy storage performance testing system comprises a micro synchronous phasor measuring device and test control equipment, the three-phase line is also provided with a three-phase current transformer and a three-phase voltage transformer which are connected into the micro synchronous phasor measuring device, and the micro synchronous phasor measuring device is connected with the test control equipment through a communication line; the test method realizes energy test, charge-discharge efficiency test, response time test, climbing rate test, reference signal tracking capability test and frequency deviation test on the energy storage system. Compared with the prior art, the method and the device meet the test requirements of different scenes, and can verify the performance and the operation condition of the energy storage system based on the micro synchronous phasor measurement in various operation modes.

Description

Intelligent microgrid energy storage system test method based on micro synchronous phasor measurement

Technical Field

The invention relates to the field of energy storage system performance testing, in particular to a method for testing an intelligent micro-grid energy storage system based on micro synchronous phasor measurement.

Background

The large-scale application of new energy, distributed energy and a mobile power supply are the revolution trend of an intelligent power grid, the emission of carbon dioxide is reduced, and the development direction of constructing a low-carbon city is the development direction of a large city. Renewable energy power generation becomes an important way for new energy utilization, and as more and more distributed power generation is connected to a power distribution network, the safe operation of the power grid is threatened, and the utilization of new energy is hindered. The intelligent micro-grid can give full play to the advantages of new energy, and provides a new idea for the utilization of the new energy. In consideration of the current requirements and long-term development requirements of new energy storage potentials at home and abroad, further subdivision and standardization of performance tests of different application scenes of energy storage is urgently needed, and the safety and reliability of the application of the energy storage system are improved.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, and provides a method for testing an energy storage system of an intelligent microgrid based on micro synchronous phasor measurement, which is suitable for performance tests of different application scenes of energy storage.

The purpose of the invention can be realized by the following technical scheme:

a method for testing an energy storage system of an intelligent micro-grid based on micro synchronous phasor measurement comprises the steps of testing the energy storage system of the intelligent micro-grid through an energy storage performance testing system; the intelligent microgrid comprises an energy storage system, an energy storage performance testing system and auxiliary electricity utilization measuring equipment, wherein the energy storage system comprises an energy storage battery pack and operation control equipment, one end of the operation control equipment is connected into the power grid through a three-phase line, the other end of the operation control equipment is respectively connected with the energy storage battery pack and the auxiliary electricity utilization measuring equipment, and the energy storage battery pack and the auxiliary electricity utilization measuring equipment are connected with each other;

the energy storage performance testing system comprises a micro synchronous phasor measuring device and a testing control device, the three-phase line is also provided with a three-phase current transformer and a three-phase voltage transformer, the three-phase current transformer and the three-phase voltage transformer are both connected to the micro synchronous phasor measuring device, and the micro synchronous phasor measuring device is connected with the testing control device through a communication line;

the operation control equipment is used for controlling an energy storage system in the intelligent micro-grid;

the micro synchronous phasor measuring device supports satellite synchronous time setting or external time setting signals and is used for synchronously measuring three-phase voltage, three-phase current, zero-sequence current and switching value information;

the test control equipment is used for reading the running data of the micro synchronous phasor measuring device in real time, recording and storing related test data, calculating test items and generating a test report;

and the auxiliary electricity consumption measuring equipment is used for acquiring the electricity consumption of the auxiliary equipment in the microgrid during the test period.

Further, the testing method comprises a data acquisition and processing flow of the micro synchrophasor measurement apparatus, and the data acquisition and processing flow of the micro synchrophasor measurement apparatus comprises the following steps:

s101: receiving a synchronous clock signal through a clock receiver, and performing frequency division processing on the synchronous clock signal through a signal frequency divider to generate sampling pulses with different frequencies;

s102: acquiring a pulse signal with a required frequency according to a preset synchronous data acquisition requirement;

s103: synchronously acquiring analog quantity signals according to the acquired pulse signals with the required frequency, wherein the analog quantity signals comprise three-phase voltage signals and three-phase current signals; collecting the three-phase voltage signals through a three-phase voltage transformer, and collecting the three-phase current signals through a three-phase current transformer;

s104: performing analog-to-digital conversion on the acquired analog quantity signal to generate a digital signal;

s105: respectively carrying out steady-state phasor calculation and dynamic phasor calculation on the digital signals, and extracting synchronous phases;

calculating frequency, amplitude, harmonic, inter-harmonic, alternating current, power and switching value according to the digital signal and the synchronous phase to obtain synchronous phasor measurement result data;

s106: circularly storing the obtained synchronous phasor measurement result data;

s107: and transmitting the obtained synchronous phasor measurement result data to the test control equipment frame by frame in real time according to the time sequence according to the control instruction of the test control equipment.

Further, the testing method comprises the following steps of testing the energy and the charging and discharging efficiency of the intelligent microgrid energy storage system, wherein the testing of the energy and the charging and discharging efficiency of the intelligent microgrid energy storage system comprises the following steps:

s201: charging the energy storage battery pack to the upper protection limit of the SOC at rated power;

s202: standing an energy storage system of the intelligent micro-grid in a hot standby state for a first standing time;

s203: setting different percentages of rated power, and calculating corresponding operation control power values;

s204: selecting a percentage of rated power from step S203, calculating a corresponding operation control power value, and performing power control on the energy storage system;

s205: the test control equipment controls the micro synchronous phasor measurement unit to acquire data, records test data, and accumulatively calculates the discharge electric quantity of the current test stage according to the recorded power and duration value;

s206: the operation control equipment stops the discharging operation when discharging to the protection lower limit of the energy storage battery pack according to the set operation control power value;

s207: after the discharging stage is finished, the test control equipment counts the discharging amount of the stage and stores data;

s208: the operation control equipment charges the energy storage battery pack according to the set operation control power value until the protection upper limit of the SOC of the energy storage battery pack is reached, and the current charging operation is stopped;

s209: the test control equipment controls the micro synchronous phasor measurement device to acquire data and calculate charging electric quantity, and after the charging stage is finished, the test control equipment counts the charging amount of the stage and stores the data;

s210: after the protection upper limit of the energy storage battery pack is charged according to the set operation control power value, the energy storage system of the intelligent micro-grid is kept stand in a hot standby state for a first standing time;

s211: judging whether the current operation control power value corresponds to 100% of rated power, if so, executing step S212, otherwise, executing step S214;

s212: presetting an initial value of the energy test times as 0, adding one to the energy test times, judging whether the energy test times meet the test times under the preset rated power, if so, performing step S213, otherwise, returning to step S205;

s213: the test control equipment calculates the average charging electric quantity, the average discharging electric quantity and the average conversion efficiency of the cycle test under the test times under the rated power according to the energy test result;

s214: the test control equipment counts the charging electric quantity and the discharging electric quantity of the test, and generates a test report according to the test result;

s215: judging whether the rated powers with different percentages set in the step S203 are tested completely, if so, executing the step S216, otherwise, returning to the step S204;

s216: and finishing the energy and charge-discharge efficiency test of the intelligent micro-grid energy storage system.

Further, in step S213, the calculation expression of the average discharge capacity is:

the calculation expression of the average charging is as follows:

in the formula, n is the number of times of testing at rated power.

Further, in step S213, the calculation expression of the average conversion efficiency is:

in the formula, n is the number of times of testing at rated power.

Further, the first standing time is within a range of 25-35 minutes.

Further, in step S203, the set different percentages of rated power include 100% rated power, 75% rated power, 50% rated power and 25% rated power.

Further, the number of tests at the rated power is 4.

Further, the test method comprises a response time and ramp rate test, which comprises the following steps:

s301: the operation control equipment charges or discharges the energy storage system to a state that the SOC of the energy storage battery pack is 50% at rated power;

s302: the operation control equipment controls the energy storage system to be kept in a hot standby state;

s303: the micro synchronous phasor measurement unit starts to collect data;

s304: charging the energy storage system until the operating power of the energy storage system reaches the preset set power, and acquiring waveform data of three-phase alternating current in real time by the test control equipment through the micro synchronous phasor measurement device;

s305: calculating response time and a climbing rate according to waveform data acquired by the test terminal through the micro synchronous phasor measuring device and the corresponding acquisition rate;

s306: presetting an initial value of the response time test frequency to be 0, adding one to the response time test frequency, judging whether the response time test frequency meets a preset rated response time test frequency, if so, performing a step S307, otherwise, returning to the step S301;

s307: the test control equipment counts the test result of the response time and generates a test report of the response time;

s308: and completing the response time and climbing rate test.

Further, the calculation expression of the response time is as follows:

response time-time for starting response to charge/discharge command when set power is reached

The calculation expression of the climbing rate is as follows:

furthermore, the value of the set power is within 88-92% of the rated power.

Further, the rated response time test number is 4.

Further, the test method further comprises a reference signal tracking capability and frequency deviation test, which comprises the following steps:

s401: setting a test curve according to the test requirement, wherein the test curve specifically comprises the total time of the test, the time interval of each test curve and the set power value of the test curve;

s402: charging or discharging the energy storage system to 50% of the SOC of the energy storage battery pack at rated power;

s403: acquiring current system time, reading a set power value in the test curve under the current system time, and issuing a corresponding control instruction to the operation control equipment;

s404: judging whether the test time of the next test curve is reached or not according to the obtained current system time, if not, waiting, and if so, performing the step S405;

acquiring and calculating power deviation from a set power value according to an actual power value of the energy storage system so as to calculate the tracking capability of a reference signal, and recording the length of time capable of tracking when the tracking capability of the reference signal is smaller than a preset trackable value;

acquiring and calculating and storing the frequency deviation of the rated frequency of the power grid according to the actual frequency of the energy storage system;

s405: acquiring the current system time, reading the set power value under the current system time, sending a corresponding control instruction to the operation control equipment, and returning to the step S404 until the execution of all the test curves is finished;

s406: counting the accumulated signal tracking time length according to the trackable time value recorded in the step S404, and calculating the percentage of tracking time; calculating the maximum frequency deviation in the test period as a total frequency deviation value according to the frequency deviation at each moment;

s407: and the test control equipment counts the tracking time percentage and the total frequency deviation value, generates a test report of the tracking capability of the reference signal and the frequency deviation and completes the test of the tracking capability of the reference signal and the frequency deviation.

Further, the calculation expression of the reference signal tracking capability is as follows:

power deviation (kW) ═ set power value (kW) — actual power value (kW)

Further, the value range of the trackable value is within the range of 0.015-0.025.

Further, the calculation expression of the tracking time percentage is as follows:

further, three-phase line has still inserted and has filled electric pile and photovoltaic power generation equipment, it is connected with electric automobile to fill electric pile.

Furthermore, the micro synchronous phasor measurement device can realize real-time data cyclic storage and dynamic recording file recording of disturbance identification, and support a short-time continuous recording function.

Furthermore, the auxiliary electricity consumption measuring equipment is used for collecting the electricity consumption of the working power supply of the energy storage inverter in the microgrid, the electricity consumption of the working power supply of the battery management system, and the electricity consumption of a fan and an air conditioner which are used for cooling and radiating in the microgrid.

Further, the operation control equipment is used for controlling the energy storage inverter to realize energy conversion between the alternating current side power grid and the direct current battery in the intelligent micro-grid.

Compared with the prior art, the invention has the following advantages:

(1) the invention aims to test the energy, efficiency, response time, climbing rate, reference signal tracking and frequency deviation of a medium energy storage system of a micro-grid by using an installed micro synchronous phasor measuring device in the smart micro-grid or by simply accessing a portable and mobile micro synchronous phasor measuring device.

(2) According to the micro synchronous phasor measurement device which can be accessed by being installed or simply connected in the intelligent microgrid, through the test method provided by the invention, a test result can be used as a reference of the performance of the energy storage system and used for evaluating the use condition and the change condition of the application performance of the energy storage system along with the time lapse, and all measured parameters such as input voltage, input current, output voltage, output current, system temperature, environmental conditions and the like are acquired at the same time resolution, so that the test of the energy storage system can be realized;

the method can be used for acceptance evaluation when the intelligent microgrid is built, can test and evaluate the performance of the microgrid key by fully utilizing high-speed data acquisition equipment installed in the microgrid without additionally developing a special communication data acquisition program and additionally installing professional wave recording equipment, and can also be used for maintenance and overhaul in daily operation of the microgrid, through the test method, the performance test of key equipment of the microgrid energy storage system can be conveniently realized, operation maintenance personnel can know the operation state of the key equipment in the microgrid in time, whether the operation control equipment meets the required technical standard or not is detected, whether the energy of the energy storage battery pack meets the requirements of regulations or not is detected, all measured parameters are recorded in an energy storage system information report and are used for further analysis and determination of the performance of the energy storage system, and the method is also suitable for application performance and measurement indexes of the energy storage system, and meets accepted measurement standards for use.

Drawings

Fig. 1 is a structural diagram of a performance test of an energy storage system according to an embodiment of the present invention;

fig. 2 is a flowchart of a data acquisition and processing method based on a micro synchronous phasor measurement unit according to an embodiment of the present invention;

fig. 3 is a flowchart illustrating a process of testing energy and charging/discharging efficiency of an energy storage system according to an embodiment of the present invention;

fig. 4 is a flowchart of a response time and a climbing rate test of an intelligent microgrid based on micro synchrophasor measurement according to an embodiment of the present invention;

fig. 5 is a flowchart of a reference signal tracking capability and frequency deviation test provided in an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or the orientations or positional relationships that the products of the present invention are conventionally placed in use, and are only used for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

It should be noted that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.

Furthermore, the terms "horizontal", "vertical" and the like do not imply that the components are required to be absolutely horizontal or pendant, but rather may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

Example 1

The embodiment provides a method for testing an energy storage system of an intelligent micro-grid based on micro synchronous phasor measurement, which comprises the steps of testing the energy storage system of the intelligent micro-grid through an energy storage performance testing system; the intelligent microgrid comprises an energy storage system, an energy storage performance testing system and auxiliary electricity utilization measuring equipment, wherein the energy storage system comprises an energy storage battery pack and operation control equipment, one end of the operation control equipment is connected into the power grid through a three-phase line, the other end of the operation control equipment is respectively connected with the energy storage battery pack and the auxiliary electricity utilization measuring equipment, and the energy storage battery pack and the auxiliary electricity utilization measuring equipment are mutually connected;

the energy storage performance test system comprises a micro synchronous phasor measurement device and test control equipment, a three-phase line is also provided with a three-phase current transformer and a three-phase voltage transformer, the three-phase current transformer and the three-phase voltage transformer are both connected to the micro synchronous phasor measurement device, and the micro synchronous phasor measurement device is connected with the test control equipment through a communication line;

More specifically, three-phase line has still inserted and has filled electric pile and photovoltaic power generation equipment, fills electric pile and is connected with electric automobile.

The micro synchronous phasor measuring device can be used for realizing real-time data cyclic storage and dynamic recording file recording of disturbance identification, and supporting a short-time continuous recording function.

And the auxiliary electricity consumption measuring equipment is used for collecting the electricity consumption of the working power supply of the energy storage inverter in the microgrid, the electricity consumption of the working power supply of the battery management system, and the electricity consumption of a fan and an air conditioner for cooling and radiating in the microgrid.

The operation control equipment is used for controlling the energy storage inverter and realizing energy conversion between an alternating current side power grid and a direct current battery in the intelligent micro-grid.

As shown in fig. 1, the functional description of each structure of the energy storage performance testing system and the energy storage system in this embodiment is specifically as follows:

101 test control device: and operating an intelligent microgrid test program, connecting the intelligent microgrid test program with a 103 micro synchronous phasor measurement device through a 102 communication line, reading the operation data of the micro synchronous phasor measurement device in real time, recording and storing related test data, calculating test items and generating a test report.

102 communication line: and connecting the test terminal with the micro synchronous phasor measuring device to realize data exchange of the two devices.

103 microsynchronous phasor measurement apparatus: the synchronous phasor measurement equipment is installed on an intelligent micro-grid, supports satellite synchronous time synchronization or external time synchronization signals, synchronously measures three-phase voltage, three-phase current, zero-sequence current and switching value information, meets the requirements of real-time data cycle storage and dynamic wave recording file recording of disturbance identification, and supports a short-time continuous wave recording function.

104 three-phase voltage transformer: collecting three-phase voltage signals of a grid-connected point of the tested equipment through a voltage transformer;

105 three-phase current transformer: collecting three-phase current signals of a grid connection point of the tested equipment through a current transformer;

106 auxiliary electricity consumption measuring equipment: the power consumption of auxiliary equipment in the microgrid in a test period is collected, such as the power consumption of a working power supply of an energy storage inverter, the power consumption of a working power supply of a battery management system, and the power consumption of equipment such as a fan and an air conditioner for cooling and heat dissipation in the microgrid.

107 operating the control device: the equipment capable of controlling the micro-grid operation, such as an energy storage inverter and the like, realizes the energy conversion between the alternating current side power grid and the direct current battery in the intelligent micro-grid,

108 energy storage battery pack: the main equipment for storing the electric energy of the intelligent micro-grid can store the electric energy generated by photovoltaic equipment or redundant electric energy generated in the power utilization valley of the power grid, and supports the operation of the micro-grid when the intelligent micro-grid needs.

According to the scheme, the energy storage system performance test method based on the micro synchronous phasor measurement is adopted to realize energy test, charge and discharge efficiency test, response time test, climbing rate test, reference signal tracking capability test and frequency deviation test on the energy storage system. Each of which is specifically described below.

Data acquisition and processing method based on micro synchronous phasor measurement device

The test method comprises a data acquisition and processing flow of the micro synchronous phasor measurement device, wherein the data acquisition and processing flow of the micro synchronous phasor measurement device comprises the following steps:

s103: synchronously acquiring analog quantity signals according to the acquired pulse signals with the required frequency, wherein the analog quantity signals comprise three-phase voltage signals and three-phase current signals; collecting three-phase voltage signals through a three-phase voltage transformer, and collecting three-phase current signals through a three-phase current transformer;

s105: respectively carrying out steady-state phasor calculation and dynamic phasor calculation on the digital signals, and extracting a synchronous phase;

The specific scheme in this example is as follows:

miniature synchronous phasor measuring device can dispose in new forms of energy node, gather the analog quantity signal in distribution network side secondary circuit, realize synchronous measurement three-phase voltage, three-phase current, zero sequence current, switching value information, real-time calculation fundamental wave phasor, the analog quantity, frequency, the frequency rate of change, function etc., it synchronizes to support synchronous time synchronization of satellite or external time synchronization signal, possess the function of guarding in time, satisfy real-time data cycle storage, and dynamic record wave file record, support the continuous record wave function in short-term, its data acquisition and processing flow are as shown in fig. 2:

201 alternating current three-phase voltage signal: the voltage signal acquisition position is shown as 104 in FIG. 1;

202 voltage transformer: the instrument is used for converting voltage, measuring the voltage value, the phase position, the frequency and the like of a line, and calculating the power and the electric energy of the line by matching with a current transformer;

203 alternating current three-phase current signal: the current signal acquisition position is shown as 105 in FIG. 1;

204 current transformer: the instrument is used for converting current, measuring the current value, phase, frequency and the like of a line, and calculating the power and the electric energy of the line by matching with a voltage transformer;

205 synchronizing clock signals: satellite synchronous time tick signal or external unified time tick signal;

206 clock receiver: the time setting signal receiving module has a self-defense function, and provides the received synchronous clock signal to the signal frequency divider after signal processing;

207 signal division: carrying out frequency division processing on the satellite synchronous signals to generate sampling pulses with different frequencies;

208 acquisition of the sampling pulse: acquiring a pulse signal with a required frequency according to the requirement of synchronous data acquisition;

209 data acquisition: synchronously acquiring voltage and current signals according to a set acquisition frequency;

210 analog/digital conversion: performing analog-to-digital conversion on the acquired analog quantity to generate a digital signal, and providing the digital signal for data processing of the next point;

211 synchronous phasor extraction: respectively performing steady-state phasor calculation and dynamic phasor calculation according to input digital quantity information, and extracting a synchronous phase;

212 phasor, ac rate, power, frequency, switching value: calculating frequency, amplitude, harmonic and inter-harmonic according to a frequency analysis module, and calculating alternating current, power and switching value according to a transient recognition module;

213 data saving: the data can be stored circularly for not less than 24 hours, the continuous wave recording can be realized in a short time, and the device can support the dynamic data recording function of 100 times per second according to the dynamic wave recording file recording of the trigger condition;

214 data communication processing interface: transmitting data such as voltage phasor, current phasor, frequency and the like and device state information and the like to a test terminal, transmitting dynamic data frame by frame in real time according to a time sequence, receiving a call command of the test terminal, and transmitting partial or all dynamic data;

215 test terminal: and running a test program, communicating with the micro synchronous phasor measurement device, issuing a control instruction, calling and testing measurement data, recording the test data, and generating a test report.

Secondly, testing energy and charging and discharging efficiency of the energy storage system

The testing method comprises the following steps of testing the energy and the charging and discharging efficiency of the intelligent microgrid energy storage system, wherein the testing of the energy and the charging and discharging efficiency of the intelligent microgrid energy storage system comprises the following steps:

s201: charging the energy storage battery pack to the protection upper limit of the SOC at rated power;

s215: judging whether the rated powers with different percentages set in the step S203 are all tested, if so, executing a step S216, otherwise, returning to the step S204;

In step S213, the calculation expression of the average discharge capacity is:

the calculation expression for average charge is:

in the formula, n is the number of times of testing at rated power.

In step S213, the calculation expression of the average conversion efficiency is:

in the formula, n is the number of times of testing at rated power.

The first standing time is within the range of 25-35 minutes. In step S203, the set different percentages of rated power include 100% rated power, 75% rated power, 50% rated power and 25% rated power. The number of tests at rated power was 4.

The specific scheme in this example is as follows: the energy storage system energy test can be divided into a cycle energy test at rated power and an energy test at 75%, 50% and 25% rated power, and the detailed process is as shown in fig. 3:

301 start energy test: entering an intelligent micro-grid energy storage energy test program;

302 Charge to SOC (State of Charge battery) protection upper limit at rated power: before starting the energy test, the energy storage system battery pack is charged to the upper protection limit of the SOC at rated power.

303 standing still for 30 minutes in a hot standby state: according to the test requirements, the energy storage system is required to be left standing in a hot standby state for 30 minutes after being charged to the protection upper limit of the energy storage battery pack at rated power.

304 select percentage of charge and discharge rated power for the test: according to different choices, the executed test flows are different, when the energy test is carried out at 100% rated power, the test is carried out according to the set times, and the test is carried out only once at other power levels.

305 tests of different percentages of rated power: through the selection of step 304, different rated power percentage tests are executed, and different operation control power values are issued.

306 start with the set power energy test: calculating a power value issued by 305 according to the percentage power selected in the step 304, and starting an energy test according to the calculated power;

307 the micro synchrophasor device starts to collect data: and the test terminal starts to synchronously acquire the data of the micro synchronous phasor device, records the test data, and accumulatively calculates the discharge electric quantity of the current test stage according to the recorded power and duration value.

308 discharge to SOC set protection lower limit: and the operation control equipment stops the discharging operation when discharging to the lower protection limit of the energy storage battery pack according to the set operation power.

309, calculating the discharge electric quantity by the test terminal through the data collected by the synchronous phasor terminal: and after the discharging stage is finished, the testing terminal counts the discharging amount of the stage and records the testing data to the database.

Standing for 30 minutes in a 310 hot standby state: according to the test requirements, after discharging to the protection lower limit of the energy storage battery pack at the set power, the energy storage system is required to stand still for 30 minutes in a hot standby state.

311 charge to SOC protection upper limit with set power: and the operation control equipment stops the charging operation when the charging is carried out to the upper protection limit of the SOC of the energy storage battery pack according to the set operation power.

312 the test terminal calculates the charge capacity through the data collected by the synchrophasor terminal: after the charging stage is finished, the testing terminal counts the charging amount of the stage and records the testing data to the database.

313 standing still for 30 minutes in a hot standby state: according to the requirements of the test method, after charging to the upper protection limit of the energy storage battery pack at the set power, the energy storage system is required to be left standing for 30 minutes in a hot standby state.

314 test at 100% rated power: and judging whether the current set power is 100% of the rated power, if so, continuing the test process 315, otherwise, ending the test process, and turning to 319 to count the test data.

315 judges whether the test times are more than 4 times: if the data of the test with 100% rated power is not more than the set times, continuing the next test; otherwise, if the set number of tests has been completed, proceed to 317 where the data from the tests is counted.

316 the next energy test is performed at the set power: and if the test task does not reach the required times, carrying out the next round of test at the set power.

The 317 test terminal calculates the average charging energy and discharging energy of the set sub-cycle test: the method takes 4 times of tests as an example, and after 4 times of tests are finished by 100% rated power, the test terminal calculates the charge electric quantity, the discharge electric quantity and the power consumption of the auxiliary equipment in the charge and discharge processes in 4 times of cycle tests.

318 calculating conversion efficiency: when 4 times of tests are finished at 100% rated power and one time of tests is finished at other percentage of energy, the average conversion efficiency of the rated power cycle test is calculated, and the charging and discharging efficiency test is used for determining the ratio of the output energy of the energy storage system to the input energy in the previous charging process.

319, counting the charging capacity and the discharging capacity of the test: in the project of testing with 100% of rated power, the testing times are only once according to the requirement of the testing method, and after one testing is completed, the testing terminal needs to count the charging electric quantity and the discharging electric quantity of the current testing.

320 write test data to test: and the test terminal writes the calculated result into a test report.

321 judges whether all the test items are completed: and if the test is not finished, performing the next test, and if the test is finished, finishing the energy and charge-discharge efficiency test project.

322 energy and charge-discharge efficiency test end: and when all the energy and charge-discharge efficiency test items are finished, the test program finishes the test.

Third, response time and climbing rate test

The test method comprises the following steps of response time and climbing rate test:

s303: the micro synchronous phasor measurement unit starts to collect data;

s308: and completing the response time and climbing rate test.

The computational expression of the response time is:

The calculation expression of the climbing rate is as follows:

the value of the set power is within 88-92% of the rated power. The nominal response time test number was 4.

The specific scheme in this example is as follows: the flow of the test of the response time and the climbing rate of the energy storage system based on the basic micro synchronous phasor measurement is shown in fig. 4, and the detailed process is as follows:

401 start response time test: and the test terminal starts a test program and starts the response time test of the intelligent micro-grid.

402 charge or discharge to SOC 50% state: if the SOC of the energy storage system in the current micro-grid is not 50%, the state that the energy storage system is charged or discharged to 50% of the SOC at the rated power is taken as the starting state of the response time test.

403 system keep hot standby: after step 302 is completed, the system should remain in a hot standby state.

404 the microsynchronous phasor measurement unit starts collecting data: after the preparation before the test is finished, the micro synchronous phasor measurement device starts to acquire data.

405 start charging at set power: the operating power adopted by the method is 90% of the rated power of the system.

406 record waveform data: the test terminal collects and records waveform data of the three-phase alternating current through the micro synchronous phasor measuring device.

407 stopping the test when the actual power reaches 90% of the rated power;

408 calculate response time: and calculating the response time of the system according to the waveform data acquired by the test terminal through the micro synchronous phasor measuring device and the acquisition rate of the device.

409 calculating response time and climbing rate: the response time calculated according to step 408 is calculated according to the following calculation formula.

Response time-time for starting response to charge/discharge command when the rated power reaches 90%

410 determines if the test item is complete: and judging whether the test items are completed or not according to the test requirements, if not, performing the next round of test, and if so, going to the step 412 to record the test data into the test report.

411 for further testing: and carrying out the next test according to the test requirements, wherein the test of the response time of the method needs 4 times.

412 write test data to test report: if all tests are complete, then test data is written to the test report.

413 response time and ramp rate test completion: and according to the test requirements, after all the response time and climbing rate test items are completed, the test terminal quits the test program, and the test is finished.

Fourthly, testing the tracking capability and the frequency deviation of the reference signal

The test method further comprises a reference signal tracking capability and frequency deviation test, which comprises the following steps:

The computational expression of the reference signal tracking capability is:

power deviation (kW) ═ set power value (kW) — actual power value (kW)

The value range of the trackable value is within 0.015-0.025.

The calculated expression for the percentage of tracking time is:

the specific scheme in this example is as follows:

the reference signal tracking test is used for evaluating the capability of the energy storage system for tracking the reference signal in the isolated grid operation application scene of the microgrid, and the frequency deviation test reflects the deviation between the actual frequency and the nominal value of the grid frequency during the operation of the microgrid. The testing flow is shown in fig. 5, and the detailed process is as follows:

501, starting the test: and starting the test software and the tested device.

502 set test curve: and setting a test curve according to the test requirement, wherein the test curve comprises the total test time, the time interval and the running power value.

503 charging or discharging at rated power to SOC 50%: and adjusting the initial state of the energy storage system during testing to be half of the rated capacity.

The set test curve is recorded 504: and reading the running value at the current time, and issuing a control instruction to the energy storage controller.

505 acquiring the current time of the system: the test system obtains the current system time.

506 the next test time has not been reached: and judging whether the test time of the next group of curves is reached or not according to the system time obtained in the last step, and waiting if the test time is not reached.

507 waiting for: the test system waits a set time.

508 calculates the difference between the set value and the actual value and saves: and calculating the power deviation and the reference signal tracking capability value, wherein the power deviation and the reference information tracking capability are calculated as shown in the following formula, and when the value is less than 0.02, the energy storage system is considered to be capable of tracking the reference signal, and the time value capable of tracking is recorded.

Power deviation (kW) ═ set power value (kW) — actual power value (kW)

509 calculate a frequency offset value and save: and calculating and storing a deviation value, wherein the frequency deviation of the isolated network operation application scene of the microgrid is not more than +/-0.5 Hz.

Frequency deviation (Hz) actual frequency (Hz) -grid rated frequency (Hz)

Acquiring 510 the current time of the system: as a basis for reading the next set of test values.

511 reading a set curve value according to the current time: and reading a control value to be issued at the current time.

512 sends the operation value to the energy storage controller: and transmitting the current operation value to the energy storage controller.

513 test curve all tests judge: and judging whether the test curve is executed completely, if not, proceeding to the next cycle, and if all tests are completed, proceeding to step 514.

514 Total Signal tracking capability: the percentage of tracking time is calculated by counting the accumulated signal tracking time length based on the traceable time value recorded in step 508.

515 statistics of the total frequency deviation: and analyzing the maximum frequency deviation in the test period as a total frequency deviation value according to the frequency deviation at each moment.

516 the test is finished.

According to the testing method provided by the invention, the energy and the charging and discharging efficiency of the energy storage system at rated power can be tested through the testing terminal and the micro synchronous phasor measuring device, the energy and the charging and discharging efficiency of the energy storage system at 75%, 50% and 25% rated power can be tested, the system response time and the climbing rate at rated power can be tested, and the reference signal tracking capability and the frequency deviation test can be carried out according to a set testing curve, so that the testing data can be calculated and stored, and a testing report can be generated, as shown in table 1.

Table 1 energy storage system performance test report

The invention aims to test the energy, efficiency, response time, climbing rate, reference signal tracking and frequency deviation of a medium energy storage system of a micro-grid by using an installed micro synchronous phasor measuring device in the smart micro-grid or by simply accessing a portable and mobile micro synchronous phasor measuring device.

The invention meets the test requirements of different scenes, and can verify the performance and the operation condition of the energy storage system based on the micro synchronous phasor measurement in various operation modes.

The key technical point of the invention is that a micro synchronous phasor measuring device which can be accessed by installing or simply connecting wires in an intelligent micro-grid, through the testing method provided by the invention, the testing result can be used as the benchmark of the energy storage system performance and used for evaluating the use condition and the change condition of the energy storage system along with the time, all the measured parameters of input voltage, input current, output voltage, output current, system temperature, environmental conditions and the like are collected on the same time resolution, the testing of the energy storage system can be realized, the method can be used as a method for acceptance and evaluation when the intelligent micro-grid is built, the method fully utilizes the installed high-speed data acquisition equipment in the micro-grid, and the testing and evaluation of the micro-grid key performance can be realized without additionally developing a special communication data acquisition program and additionally installing special wave recording equipment, the method can be used for the performance test of key equipment of the micro-grid energy storage system, the operation maintenance personnel can know the operation state of the key equipment in the micro-grid in time, whether the operation control equipment meets the required technical standard or not is detected, whether the energy of the energy storage battery pack meets the requirements of regulations or not is detected, and all measured parameters are recorded in an energy storage system information report and are used for further analyzing and determining the performance of the energy storage system.

The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.

Claims

1. A method for testing an energy storage system of an intelligent micro-grid based on micro synchronous phasor measurement is characterized by comprising the steps of testing the energy storage system of the intelligent micro-grid through an energy storage performance testing system; the intelligent microgrid comprises an energy storage system, an energy storage performance testing system and auxiliary electricity utilization measuring equipment, wherein the energy storage system comprises an energy storage battery pack and operation control equipment, one end of the operation control equipment is connected into the power grid through a three-phase line, the other end of the operation control equipment is respectively connected with the energy storage battery pack and the auxiliary electricity utilization measuring equipment, and the energy storage battery pack and the auxiliary electricity utilization measuring equipment are connected with each other;

2. The method for testing the smart micro-grid energy storage system based on micro synchronized phasor measurement according to claim 1, wherein the testing method comprises a data acquisition and processing flow of the micro synchronized phasor measurement device, and the data acquisition and processing flow of the micro synchronized phasor measurement device comprises the following steps:

3. The method for testing the energy storage system of the intelligent microgrid based on the microsynchronous phasor measurement is characterized in that the testing method comprises an energy and charge-discharge efficiency test of the energy storage system of the intelligent microgrid, and the energy and charge-discharge efficiency test of the energy storage system of the intelligent microgrid comprises the following steps:

4. The method for testing the energy storage system of the smart micro-grid according to claim 3, wherein in step S213, the average discharge capacity is calculated by the following expression:

the calculation expression of the average charging is as follows:

in the formula, n is the number of times of testing at rated power.

5. The method for testing the energy storage system of the smart micro-grid according to claim 3, wherein in step S213, the calculation expression of the average conversion efficiency is as follows:

in the formula, n is the number of times of testing at rated power.

6. The method for testing the energy storage system of the smart micro-grid based on micro-synchronous phasor measurement according to claim 3, wherein the first resting time is within a range of 25-35 minutes.

7. The method for testing the energy storage system of the smart micro-grid according to claim 3, wherein the different percentages of rated power set in step S203 comprise 100% rated power, 75% rated power, 50% rated power and 25% rated power.

8. The method for testing the energy storage system of the smart micro-grid based on the micro-synchronous phasor measurement according to claim 3, wherein the number of tests at the rated power is 4.

9. The method for testing the energy storage system of the smart micro-grid based on the micro-synchronized phasor measurement according to claim 1, wherein the testing method comprises a response time and ramp rate test, and the response time and ramp rate test comprises the following steps:

s303: the micro synchronous phasor measurement unit starts to collect data;

s308: and completing the response time and climbing rate test.

10. The method for testing the smart micro-grid energy storage system based on micro-synchronized phasor measurement according to claim 9, wherein the calculation expression of the response time is as follows:

The calculation expression of the climbing rate is as follows:

11. the method for testing the energy storage system of the smart micro-grid based on the micro-synchronized phasor measurement according to claim 9, wherein the set power is within a range of 88-92% of a rated power.

12. The method for testing the energy storage system of the smart micro-grid according to claim 9, wherein the rated response time is 4 times.

13. The method for testing the smart micro-grid energy storage system based on micro-synchronized phasor measurement according to claim 1, further comprising a reference signal tracking capability and frequency deviation test, wherein the reference signal tracking capability and frequency deviation test comprises the following steps:

14. The method for testing the smart micro-grid energy storage system based on micro-synchronized phasor measurement according to claim 13, wherein the calculation expression of the reference signal tracking capability is as follows:

power deviation (kW) ═ set power value (kW) — actual power value (kW)

15. The smart micro-grid energy storage system testing method based on micro-synchronized phasor measurement according to claim 14, wherein the trackable value is within a range of 0.015 to 0.025.

16. The method for testing the smart micro-grid energy storage system based on micro-synchronized phasor measurement according to claim 13, wherein the calculation expression of the tracking time percentage is as follows:

17. the method for testing the intelligent micro-grid energy storage system based on the micro-synchronous phasor measurement according to claim 1, wherein a charging pile and a photovoltaic power generation device are further connected to the three-phase line, and the charging pile is connected with an electric vehicle.

18. The method for testing the energy storage system of the intelligent microgrid based on the micro synchronous phasor measurement is characterized in that the micro synchronous phasor measurement device meets the requirements of real-time data cycle storage and dynamic recording file recording of disturbance identification, and supports a short-time continuous recording function.

19. The method for testing the energy storage system of the intelligent microgrid based on the micro synchronous phasor measurement, according to claim 1, characterized in that the auxiliary electricity consumption measurement equipment is used for collecting the electricity consumption of an energy storage inverter working power supply in the microgrid, the electricity consumption of a battery management system working power supply, the electricity consumption of a fan and an air conditioner used for cooling and heat dissipation in the microgrid.

20. The method for testing the energy storage system of the smart micro-grid based on the micro-synchronous phasor measurement according to claim 1, wherein the operation control device is used for controlling the energy storage system, and energy conversion between an alternating-current side grid and a direct-current battery is realized in the smart micro-grid.