Home > Solution> Solar Power Generation System Design> Off-Grid Solar Power System Design

Hot Product

108-111 System performance test

Author: Source: Datetime: 2017-01-19 09:12:58 System performance test

The system shall perform performance tests in accordance with the relevant standard test procedures. In the course of the test, the tester shall strictly comply with the manufacturer's instructions for operation, installation and connection. Performance test in the outdoors, indoor can be carried out. If the outdoor test conditions at the test site are similar to the simulated outdoor conditions in the standard, an outdoor test may be performed. If the difference is significant, an indoor test is recommended. The test conditions cover the major climate zones where the system is designed and used. The test requires two samples to be taken from the same type of system. If one system fails in any one test, then another system meeting the criteria will re-accept the entire test. If the system is also not up to standard, the design will be deemed to fail to meet the verification requirements.
System performance testing of the three stages
System performance test is divided into three stages: pretreatment, performance testing, the maximum voltage load operation of the applicability.
(1) pretreatment
The purpose of the pretreatment test is to determine the system when the normal operation of the HVD (the battery is full open when the voltage), LVD (battery undervoltage disconnect voltage). Before the test, the battery shall be preconditioned in accordance with the manufacturer's instructions (this is not done if the battery is not preconditioned in the system documentation). If the PV module is amorphous, a photodefying test should be performed.
(2) performance test
The performance test has the following six steps.
① initial capacity test (UBC0): in accordance with the standard requirements after the installation of the system, the battery charge and discharge, measurement of battery capacity, which was the initial battery capacity available (UBC0). ;
② battery charging cycle test (BC): to recharge the battery.
③ system function test (FT): the main test system and load operation is normal /
④ The second capacity test (UBC1): Through the battery charge and discharge, measure the battery's first available capacity (UBC1) and the system's independent operation days.
⑤ recovery test (RT): to determine the PV system has been discharged on the rechargeable battery capacity;
(6) Final capacity test (UBC2): The second available capacity (UBC2) of the battery is measured by charging and discharging the battery. After the 6 steps of the performance test, the system characteristic curve is drawn according to the test data to determine the equilibrium point of the system and obtain the minimum average irradiation amount of the installation site where the system is running normally.
(3) the maximum voltage when the applicability of the load operation
 Load test at maximum voltage Verifies the suitability of the load to operate at maximum irradiance and maximum voltage at high charge. In these strips
The load under the load will run without damage. System performance test from the functional, independent operation and the battery after the state has been restored over the state of the ability to conduct a comprehensive test, which gives the system will not be a reasonable confirmation of failure. Qualified basis for the performance test is as follows.

① The load must remain operational throughout the test unless the charge controller is disconnected from the load in case the battery is overdriven (this data should be indicated if an LVD has occurred).
② battery capacity decline in the entire test period can not exceed 10%.
③ recovery: the system voltage in the recovery test should show an upward trend in the entire recovery test, into the battery safety time (A * h) should be greater than or equal to UBC1 50%.
Precautions for System Performance Test
For the system design verification, the performance test has indoor and outdoor of the points. Most manufacturers generally do not have the indoor test equipment conditions, this part is usually commissioned by a qualified specialized testing and testing institutions to carry out, and outdoor test part must do. Here, we mainly introduce the outdoor test must pay attention to matters.
(1) Standard irradiance and system classification
Derivation of the mean annual daily radiation dose and the radiation dose range from the meteorological station close to the installation site.

The H range is the difference between the daily average of the highest monthly mean and the monthly average of the lowest monthly average of irradiance [unit kW.h / (m2. D)]. Each site corresponds to an irradiance level (Table 4-16).

Table 4-16 Irradiation levels

Irradiation level 1 2 3 4 5 6
Annual average daily surface radiation/[kW • h/(m2 • d)] <4.5 <4.5 4.5 〜5.5 4.5 〜5.5 >5.5 >5.5
Range/[kW. h/(m2•d)] >1.5 <1.5 >1.5 <1.5 >1.5 <1.5
Note: The calculation of the daily operating time is based on exposure level 2.

(2) load specifications
The manufacturer shall provide the system while providing the actual load to be supplied by the system in the design. In the case of multiple loads, the manufacturer shall establish the switching sequence. In this case, there shall be a mark indicating the necessary switching sequence on the switchboard or at the appropriate place that is apparent to the end-user. In all tests, all loads were operated simultaneously.
The manufacturer shall specify the number of hours per day that the system will be able to supply the load under the relevant standard (daily operating time) test conditions. This data should be based on the exposure level n defined in the table above.
For inspection purposes, the load should not be operated during daylight hours or irradiance greater than 50 W / m2 when the PV module has been connected.
(3) system installation and pretreatment
Install the system according to the manufacturer's installation instructions. For outdoor tests, ensure that the solar array is not obstructed by any object, such as a building or plant, during the test. For indoor tests, a C-class solar simulator or an electronic power supply for the analog component can be used. During the system assembly, the data acquisition device can be easily installed according to the configuration of the system. The tester can not modify and add to the system under test: only install the original system according to the stipulations in the document. If the cable is disconnected during installation, the tester shall use the full length cable received with the system.
Note that the charge controller must be carefully installed, in strict accordance with the order of connection to avoid damage.
For the system to work, add the electrolyte and pretreatment battery according to the manufacturer's instructions. If the battery does not require preprocessing in the system file, the system accepts:
• At least 5 cycles from HVD to LVD in outdoor tests;

• In laboratory tests, At least 5 cycles.
Some advanced charge controllers require several days or several iterations to find the best settings to match the system design. The manufacturer shall explain this and the performance test will preclude the number of cycles before.
According to IEC 61646, a photovoltaic module having photovoltage characteristics, such as amorphous silicon, will receive the initial light. Install the total radiation table (standard device) for the array plane. The total radiation table will be as close to the array as possible and do not leave any shadow on the array.
The data acquisition is programmed to monitor the measured data and is stored once every 5 min. Installing the Temperature Sensor CAUTION:
• The ambient temperature sensor must be installed in a ventilated or double shaded enclosure.
• The temperature sensor on the back of the module must be installed in the center of the battery in the middle of the module. Fixed with a thermal adhesive and covered with an insulating material and metal foil.
The battery's temperature sensor must be installed as close to the temperature-compensated sensor as possible. If the temperature compensation is in the charge controller, in addition to the battery temperature sensor should also be added to the controller temperature sensor. Install a voltage sensor on the PV array and on the load. Install the battery voltage sensor on the battery terminals.
The load is a part of the system and its size is a very important design parameter. For the purpose of the test, all loads shall be installed and operated at the same time. Verify that the load starts and runs correctly.
When there are multiple loads in the system, observe whether a single load can be started and run when all other loads are running.
In this test, sometimes only to make the load work long enough to confirm its function is normal. For example, lighting a low pressure sodium lamp until the brightest, usually takes 15min.
Outdoor performance test
Several of the keywords used are as follows.
UBC0 (Initial Battery Available Capacity): Initial Capacity Test - After installation, the battery is charged and discharged, and the battery capacity (UBC) is measured.
Vreg: The controller determines the voltage level at which the battery is fully charged.
BC (Battery Charging): Recharge the battery before the functional test.
FT (Functional Test): Run Functional Tests Verify that the system and load are operating properly.
UBC1 (battery primary available capacity): the second capacity of the test and independent operation days - the battery charge and discharge. Measure the available battery capacity. Determine the number of days the system will run independently.
RT (Recovery Test): Determine the rechargeability of the PV system to the discharged battery.
UBC2 (secondary battery usable capacity): final capacity test - the battery to charge and discharge. Observe the available battery capacity.
Various test sequences were used in the assays to verify low-discharge, battery recovery, functional operation, and HVD capability during normal operation after fully discharged, fully sunny conditions.
Outdoor test condition determination: During the test, the temperature of the battery and charge controller shall be maintained at 30 ° C ± 3 ° C; during the test, the temperature of the module shall be monitored. On a day-to-day basis, hourly averages should be calculated and averaged irradiance values plotted over the same period. At the end of each day, these values are compared to the values in Table 4-17. If the data falls between the values listed in the table, you can use the linear interpolation method.
NOTE: This procedure ensures that the energy output of the array of components under both methods is no more than ± 5% compared to the indoor measurement method (crystalline silicon cell) under harsh conditions.
If the average hourly temperature of the component exceeds the following limits, all tests shall be repeated.
If low solar radiation days must be simulated, for example, in a functional test, the only option is to tilt the PV array to reduce input energy to obtain simulated harsh climatic conditions. Disconnecting the PV module is not permitted after the required power input is reached at full power.
Table 4-17 Determine acceptable component temperature ranges based on irradiance



Acceptable component temperature range/°c Irradiance/(W/m2) Acceptable component temperature range
100 14 〜34 600 40 〜60 
200 18 〜38 700 43 〜63
300 21 〜41 800 50 〜70
400 28 〜48 900 54 〜74
500 32 〜52 1000 58 〜78
The tests were carried out in the following order.
(1) initial capacity test
Disconnect the load, use the PV array to charge the battery. Once the system reaches the specified state, allowing the system to maintain this state 72h (cumulative), can be considered that the battery has been charged to the test target.
Disconnect the PV array, so that the load continuously, allowing the battery discharge to the LVD state, when the LVD can be considered to complete the battery discharge. Let the battery in the LCD state to maintain at least 5h, record the battery discharge A.h number and battery temperature range. This is the initial available battery energy (UBC0).
(2) battery charging cycle
The load is disconnected and the charge is reached (HVD) again using the PV array, allowing up to 0.5h to be maintained in this state.
(3) system function test
This test verifies that the system can be designed to supply power to the load.
In accordance with the requirements of the manufacturer will be connected to the PV array and the load, so that the system work 10d. The test cycle should include at least 2 consecutive days of low radiation and at least 3 distinctly different amounts of daily radiation. Need to use these three radiation volume to draw the system characteristic map, and thus derive the system balance point. Therefore, it is necessary that the two irradiation amounts correspond to a higher irradiation amount than the equilibrium point of the system. The average daily irradiance of 10 days should be 4 kW • h / (m2 • d) ± 0.3 kW • h / (m2 • d).
If the test lOd 2d does not meet the requirements and does not meet the requirements of radiation 4kW, hAm2.d), need to extend 20d until the last 10d to meet the requirements, if not yet re-start the test.
(4) the second capacity test
Disconnect the load after the functional test. Turn on the PV array, charge the battery again to reach HVD, and at this point for 0.5h, disconnect the PV array from the load and allow the system to discharge until LVD.
Determine the battery discharge (A «h) and the total discharge time, which is the second battery available capacity (UBCD. Keep the system at the LVD point at least 5h, but not more than 72h.
(5) recovery test
Connect the PV array and disconnect the load. When the irradiated amount of radiation reaches 5 kW * h / m2, the load shall be connected according to the manufacturer's definition.
Note 1: At this time the system may still be in a low voltage protection state.
Note 2: The system does not have to receive 5kW • h / m2 of radiation in one day.
The combination of a charge cycle of 5 kW • h / m2 and a continuous duty cycle defined by the manufacturer is called a recovery test cycle.
These recovery test cycles were repeated until the total radiation of the system was 35 kW • h / m2. If the system reaches HVD, record the number of recovery test cycles required for the battery to reach HVD.
Record which recovery test cycle the load starts to start.
Measurements were made (A * h) charged to the battery and load discharge in 7 recovery test cycles.
(6) Final capacity test
After the test cycle is resumed, the load is disconnected and waited until the system reaches the specified charge state. Once the system has reached this state, it remains in this state 72h, at which point the battery can be considered to be full.
Disconnect the PV array from the load and allow the system to discharge completely. When the LVD state is reached, the battery is considered to be fully discharged and kept in this state for at least 5 h. Record the battery discharge (A • h) and the battery temperature range. This is the ultimate battery capacity
(7> operating at maximum voltage
Verify the suitability of the load for operation at high irradiance and maximum voltage at high charging conditions. Under these conditions will operate 1h, the load should not be damaged.
Any abnormal events are recorded throughout the test, including unexpected shorts or open circuits, data acquisition system failures, and so on.

Page: 108-111

TAG: Prices FIT distributed Projects Farm olar Trend Bicycles Layoffs Zhengtai Powerwall Inverus SolarOne Portfolio Residential