S3-RD reactive power transmitterIt is an instrument that can isolate and amplify input voltage and current signals, convert them into DC signals that are linearly proportional to the input reactive power, and output them. It can reflect the characteristics of the system load (capacitive or inductive), and can operate continuously for a long time. It is widely used in power systems and non power systems with high requirements for measuring reactive power. The following is an introduction to its verification method.

1、 Preparation work for verification

1. Standard equipment preparation: Select high-precision standard power meters, DC voltmeters, DC milliammeters, etc. as calibration reference equipment to ensure their accuracy meets the calibration requirements and passes regular calibration and verification. At the same time, prepare stable power supply equipment that can provide voltage and frequency that meet the rated input requirements of the reactive power transmitter.

2. Wiring tools and materials: Prepare appropriate specifications of wires, wiring terminals, short-circuit plates, and other wiring tools and materials to ensure reliable connections and low contact resistance, in order to avoid introducing additional measurement errors. The wire should have good insulation performance and appropriate current carrying capacity to meet the current transmission requirements during the verification process.

3. Environmental condition control: Calibration should be carried out in an environment where the temperature, humidity, and other environmental conditions meet the specified usage range of the transmitter, avoiding harsh environments such as strong electromagnetic interference, vibration, and high dust to ensure the accuracy of the calibration results.

2、 Appearance and wiring inspection

1. Appearance inspection: Firstly, conduct a comprehensive appearance inspection of the reactive power transmitter to check whether its housing is damaged, deformed, cracked, etc., whether the nameplate identification is clear and complete, including model, specifications, accuracy level, input and output parameters, and other information. Check whether the wiring ports of the transmitter are loose, oxidized, or have foreign objects, ensuring that the transmitter has a good appearance and the wiring ports are normal.

2. Wiring correctness check: Based on the wiring diagram and working principle of the transmitter, carefully check whether the wiring of the input voltage, current circuit, and output signal circuit is correct. The input voltage should be connected to the corresponding voltage input terminal, and the current circuit should be connected in series to the corresponding current input terminal, paying attention to the correctness of polarity. The output signal circuit should be correctly connected to the load or testing equipment, such as a DC milliampere meter or data acquisition device, to ensure that the signal transmission path is unobstructed.

3、 Basic error verification

1. Three phase method verification (applicable to three-phase balance systems)

Wiring method: According to the three-phase method verification wiring diagram, connect the standard power meter in parallel with the input terminal of the S3-RD reactive power transmitter, so that both are under the same voltage and current input conditions. At the same time, connect the output terminal of the transmitter to a DC milliampere meter or data acquisition device to monitor changes in the output signal.

Verification steps: Firstly, with a reactive power factor of 1.0 (inductive), apply a nominal voltage and gradually change the current. Then, at different current values such as 100Ib, 80% Ib, 60% Ib, 40% Ib, 20% Ib, etc., make the algebraic sum of the standard power meter readings equal to the input standard value. At the same time, record the DC milliampere meter reading Ix of the output circuit. Next, with sin φ=0.5 (inductive), repeat the above operation, change the current, and record the corresponding output reading. Finally, based on the recorded data, calculate the basic error using the error formula and evaluate the measurement accuracy of the transmitter. For bidirectional output transmitters, it is necessary to change the direction of each phase current, repeat the above verification process, and determine their basic error in reverse output.

2. Single phase method verification (applicable to partially unbalanced systems or special situations)

Wiring method: Refer to the wiring diagram verified by single-phase method, connect the standard power meter to the input terminal of the transmitter appropriately, and simulate the input situation of single-phase reactive power. Similarly, connect the output of the transmitter to the testing equipment.

Verification steps: Under the specified reactive power factor conditions, apply single-phase voltage and current, gradually change the current magnitude or power factor, so that the reading of the standard power meter reaches the set standard value. At the same time, read and record the DC milliampere meter reading at the transmitter output terminal. By comparing the difference between the output of the transmitter under different input conditions and the standard value, the basic error is calculated to determine whether the measurement accuracy of the transmitter under single-phase conditions meets the requirements.

4、 Other characteristic verification

1. Frequency response verification: While keeping the input voltage and current amplitude constant, change the frequency of the input signal and observe the changes in the transmitter output signal within a certain frequency range (such as 40-600Hz). Check whether its output remains stable within the specified frequency range and does not produce additional errors beyond the allowable range due to changes in signal frequency, in order to verify whether its frequency response characteristics meet the technical specifications of the product.

2. Linearity verification: By uniformly changing the magnitude of the input reactive power, the output signal of the transmitter is measured at multiple different power points, and the relationship curve between the output signal and the input reactive power is plotted. Check whether the curve exhibits good linear characteristics, that is, whether there is a proportional relationship between the output signal and the input reactive power, and the deviation should be within the specified linearity error range.

3. Reverse power measurement capability verification (if necessary): For reactive power transmitters with reverse power measurement function, simulate the input situation of reverse reactive power by changing the current direction or adjusting the power factor. Observe whether the transmitter can correctly identify and measure reverse reactive power, and whether the changes in its output signal meet the expected characteristics and accuracy requirements of reverse power measurement.

5、 Analysis and processing of verification results

1. Data organization and analysis: Organize all data recorded during the verification process, including standard power meter readings under different input conditions, transmitter output readings, and calculated basic errors. Perform statistical analysis on the data, draw error distribution charts, visually observe the trend and distribution of errors, determine whether the errors are within the allowable error range of the transmitter, and analyze the reasons for the errors.

2. Result judgment: Based on the analysis of the calibration data, compare the accuracy level and technical specifications of the reactive power transmitter to determine whether the calibration result of the transmitter is qualified. If all calibration items are within the allowable error range, the transmitter calibration is considered qualified; If there are individual items that exceed the allowable error, further analysis of the reasons is necessary. If necessary, repeat calibration or adjust or repair the transmitter before re calibration until the calibration results meet the requirements.

3. Issue verification report: After verification is completed, a detailed verification report should be issued in accordance with the prescribed format. The calibration report should include basic information of the transmitter (such as model, specifications, number, etc.), calibration date, calibration environmental conditions, calibration equipment used, calibration items, calibration data, result judgment conclusion, and signature of the calibration personnel. The verification report, as an important basis for transmitter performance and measurement accuracy, should be properly stored for future reference and traceability.

6、 Precautions

1. Safe operation: During the verification process, it is necessary to strictly follow the electrical safety operating procedures for wiring and powering on electrical equipment. Ensure that wiring and disconnecting operations are carried out in a power-off state to prevent electric shock accidents from occurring. At the same time, pay attention to checking the insulation and grounding of the power cord to avoid safety accidents caused by electrical faults.

2. Equipment grounding: In order to ensure the accuracy and safety of the calibration, the reactive power transmitter and all electrical equipment participating in the calibration should be reliably grounded. The grounding resistance should meet the requirements of relevant standards to avoid introducing interference signals or causing equipment damage due to poor grounding.

3. Signal stability: When reading verification data, ensure that the input and output signals are stable before reading. Avoid reading data when the signal fluctuates greatly to avoid measurement errors. For some input signals that may have fluctuations, the stabilization time can be appropriately extended or multiple averaging readings can be used to improve measurement accuracy.

4. Environmental interference suppression: Although environmental conditions have been controlled before verification, attention should still be paid to the possible impact of environmental factors on the verification results during the verification process. If there is strong electromagnetic field interference around, effective shielding measures should be taken to reduce the impact of interference signals on the transmitter and calibration equipment. At the same time, avoid using other electronic devices that may cause electromagnetic interference at the verification site, such as mobile phones, intercoms, etc.

5. Equipment maintenance and upkeep: After the calibration is completed, the S3-RD reactive power transmitter and all calibration equipment should be cleaned and maintained to restore them to their normal storage state. Regularly calibrate and maintain the calibration equipment to ensure its performance is always in an ideal state, in order to ensure the accuracy and reliability of subsequent calibration work.

In summary, the calibration of S3-RD reactive power transmitters is a rigorous and meticulous task that requires strict adherence to relevant calibration methods, operating procedures, and technical standards. By following the correct verification process and operation, the performance and measurement accuracy of the transmitter can be accurately evaluated, problems can be discovered and solved in a timely manner, ensuring its reliable operation in the power system and other related fields, and providing strong guarantees for the accurate measurement of reactive power and the stable operation of the power grid.