CN108181605A - A kind of meter and the electric energy meter and detection method of temperature and Constant charge soil joint effect - Google Patents

Abstract

An electric energy meter and detection method that take into account the joint influence of temperature and constant magnetic field, the electric energy meter includes a current transformer CT, a first resistor R1, a second resistor R2, a third resistor R3, an A/D converter, a DSP, Display, storage unit and communication unit; also includes magnetic field sensing unit and temperature sensor. The magnetic field sensing unit and temperature sensor in the electric energy meter respectively collect the magnetic induction intensity and temperature information of the constant magnetic field during on-site operation, and transmit the information in the electric energy meter to the external network; Extract the information within a certain period of time, control the constant magnetic field generator and the high and low temperature box to simulate the on-site operating environment, simulate the actual on-site operating environment in the laboratory, and obtain the comprehensive error of the tested meter to evaluate the performance of the electric energy meter.

Description

An electric energy meter and its detection method considering the joint influence of temperature and constant magnetic field

technical field

The invention relates to an electric energy meter and a detection method considering the joint influence of temperature and a constant magnetic field, belonging to the technical field of electric energy meters.

Background technique

As one of the important devices of the smart grid, the accurate measurement and reliable operation of the smart energy meter directly affects the electricity bill settlement between the electricity user and the power supply company. Before on-site installation, according to the relevant national standards or enterprise standards, the electric energy meter will be subjected to random inspection before arrival and full performance test after arrival. In addition, periodic on-site inspections will be carried out on the energy meters in operation. On-site testing is mainly based on DLT448-2016 "Technical Management Regulations for Electric Energy Metering Devices". The conditions for on-site calibration are as follows: ambient temperature is (5-35) ℃; relative humidity is not greater than 85%; frequency deviation is less than ±0.5% of rated frequency The deviation of the voltage from the rated value should not exceed ±10%. The power of the on-site load should be the actual common load. calibration. On-site testing is actually a loose testing method, because the on-site calibrator is also in the complex environment of the site, and it cannot be guaranteed that it has the same measurement performance as that under laboratory conditions. However, testing only under laboratory conditions cannot accurately reflect the performance of the energy meter in the actual operating environment on site.

Contents of the invention

The object of the present invention is to propose an electric energy meter and a detection method that take into account the joint influence of temperature and constant magnetic field, aiming at the problems existing in the field detection of the existing electric energy meter.

The technical scheme for realizing the present invention is as follows: a method for detecting an electric energy meter that takes into account the joint influence of temperature and a constant magnetic field, wherein the method sets a magnetic field induction unit and a temperature sensor in the electric energy meter; collects the magnetic induction of the constant magnetic field during field operation and temperature information, and transmit the data in the electric energy meter to the external network; during detection, according to the meter number of the meter under inspection, extract information within a certain period of time from the master station, and control the constant magnetic field generator and the high and low temperature box to simulate the on-site operating environment , simulate the actual operating environment in the laboratory, and get the comprehensive error of the tested meter.

The electric energy meter includes: a current transformer CT, a first resistor R1, a second resistor R2, a third resistor R3, a temperature sensor, a magnetic field sensing unit, an A/D converter, a DSP, a display, a storage unit and a communication unit; The primary side winding of the transformer CT is connected to the neutral line N; the secondary side winding of the current transformer is connected in parallel with the first resistor R1, one end is connected to the input end of the A/D converter, and the other end is grounded; the second resistor R2 and the first resistor R1 are connected in parallel. Three resistors R3 are connected in series, and are respectively connected to the phase line L and the neutral line N; the common connection end of the third resistor R3 and the second resistor R2 is connected to the input end of the A/D converter, and the other end is grounded; the magnetic field sensing unit is close to the current The transformer CT is installed and connected to the input end of the A/D converter; the temperature sensor is connected to the input end of the A/D converter; the output end of the A/D converter is connected to the output end of the DSP; the DSP is also connected to the communication unit, display and storage unit connections.

The working principle of the electric energy meter is as follows: the current transformer CT converts the current supplied to the load into a small current analog signal, and converts it into a digital signal through the A/D converter and outputs it to the DSP; resistors R2 and R3 will supply power to the load The voltage is divided by the resistance to obtain a small voltage analog signal, which is converted into a digital signal by the A/D converter and output to the DSP; the magnetic field sensing unit transmits the detected magnetic induction intensity of the constant magnetic field close to the current transformer CT to the DSP; the temperature sensor The temperature signal in the energy meter is transmitted to the DSP; the DSP processes and analyzes the digital information, saves the data to the storage unit, and displays the specific value through the display; the communication unit can transmit the data in the energy meter to the external network.

The steps of transmitting the data in the electric energy meter to the external network are as follows:

(1) Set the time interval Δt of data collection;

(2) Record the current time t;

(3) The temperature sensor and the magnetic field sensing unit start to collect data;

(4) Save the data to the storage unit in the electric energy meter;

(5) Set the time interval t _m of transmission;

(6) Judging whether t+Δt≤t _m is satisfied, if satisfied, return to step (2); if not satisfied, enter step (7);

(7) transmit data to external network;

(8) Clear the data in the storage unit and return to step (2).

The detection method of the electric energy meter is as follows:

When a certain electric energy meter running on site is suspected to be faulty, the electric energy meter can be disassembled and used as the inspected meter; according to the meter number information of the inspected meter, the storage unit of the inspected meter is called from the main station to save the temperature, Magnetic induction intensity, voltage and current information with time scale data; according to the above data, the comprehensive error of the tested meter is obtained through the test of simulating the influence of on-site temperature and the test of simulating the influence of on-site constant magnetic field in the laboratory.

The comprehensive error testing method of the checked table is as follows:

(1) Set up the tested meter test device: the device includes a standard meter, a standard power source, an error calculation unit, a high and low temperature box, and a constant magnetic field generator; the voltage circuit of the standard meter is connected in parallel with the voltage circuit of the tested meter; the standard meter The current circuit of the tested meter is connected in series with the current circuit of the tested meter; the pulse ports of the standard meter and the tested meter are connected to the error calculation unit; Error under operating conditions;

(2) In the test of simulating the influence of on-site temperature, the tested meter is placed in a high and low temperature box; according to the voltage and current curve of the tested meter in a certain period of time, the standard power source is controlled to output voltage and current test signals in line with the current operating environment ;Control the high and low temperature box so that the temperature is the reference temperature of 23°C, get l at this time, and record it as α ₁ ; according to the temperature data of the tested meter in a certain period of time, control the temperature in the high and low temperature box and the on-site operating environment Temperature approximation, get the relative error of the tested meter at this time, and record it as α ₂ ;

(3) In the test of simulating the influence of the constant magnetic field on site, the tested meter is placed in the constant magnetic field generator, and according to the voltage and current curve of the tested meter in a certain period of time, the standard power source is controlled to output the voltage and current in line with the current operating environment Test signal; according to the constant magnetic field magnetic induction data of the tested meter in a certain period of time, control the constant magnetic field generator to generate a constant magnetic field magnetic induction similar to the field operating environment, and obtain the relative error of the tested meter at this time, and record it as α ₃ ;

(4) Calculate the comprehensive error α of the checked meter, the calculation formula of α is as follows:

The beneficial effect of the present invention is that the present invention provides an electric energy meter detection method that takes into account the joint influence of temperature and constant magnetic field. The actual operating environment data is obtained through the temperature sensor and the magnetic field sensing unit in the electric energy meter, and the data is transferred by the internal communication unit. It is transmitted to the external network. During the test, the environmental information can be extracted from the master station according to the meter number of the inspected meter, and simulated in the laboratory, and then the comprehensive error of the inspected meter can be obtained, which overcomes the traditional on-site inspection method due to standard calibration. The device is in the field environment, which leads to the disadvantage that its accuracy level cannot meet the detection requirements.

Description of drawings

Fig. 1 is the principle schematic diagram of electric energy meter of the present invention;

Fig. 2 is the schematic diagram of the principle of data transmission in the electric energy meter of the present invention;

Fig. 3 is the flowchart of data transmission in the electric energy meter of the present invention;

Fig. 4 is a schematic flow chart of the electric energy meter detection method of the present invention;

Figure 5 shows the schematic diagram of the test for simulating the influence of on-site temperature;

Figure 6 shows the schematic diagram of the experiment for simulating the influence of the field constant magnetic field.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment the present invention is described in further detail:

Figure 1 is a schematic diagram of the principle of the electric energy meter of the present invention.

This embodiment is an electric energy meter that takes into account the joint influence of temperature and constant magnetic field, including a current transformer CT, a first resistor R1, a second resistor R2, a third resistor R3, a temperature sensor, a magnetic field sensing unit, and an A/D converter , DSP, display, storage unit and communication unit. The primary winding of the current transformer CT is connected to the neutral line N; the secondary winding of the current transformer is connected in parallel with the first resistor R1, one end is connected to the input end of the A/D converter, and the other end is grounded; the second resistor R2 and The third resistor R3 is connected in series with the phase line L and the neutral line N respectively; one end of the third resistor R3 is connected to the input end of the A/D converter, and the other end is grounded; the magnetic field sensing unit is installed close to the current transformer CT, and Connected to the input of the A/D converter; the temperature sensor is connected to the input of the A/D converter; the output of the A/D converter is connected to the output of the DSP; the DSP is also connected to the communication unit, display and storage unit respectively connect.

The current transformer CT converts the current supplied to the load into a small current analog signal, and converts it into a digital signal through the A/D converter and outputs it to the DSP; the second resistor R2 and the third resistor R3 divide the voltage supplied to the load through resistors The small voltage analog signal is obtained by the A/D converter, which is converted into a digital signal by the A/D converter and output to the DSP; the magnetic field sensing unit transmits the detected magnetic induction intensity of the constant magnetic field close to the current transformer CT to the DSP; The temperature signal is transmitted to the DSP; the DSP processes and analyzes the digital information, saves the data to the storage unit, and displays the specific value through the display; the communication unit can transmit the data in the energy meter to the external network.

Fig. 2 is a schematic diagram of data transmission in the electric energy meter of the present invention.

The electric energy meter of this embodiment transmits the time-stamped data containing temperature, magnetic induction intensity, voltage and current information stored in the storage unit to the external network through the internal communication unit; the transmission between the communication unit and the external network can be adopted Broadband carrier communication, RS485 or micro-power wireless, etc.; the external network communicates with the master station through GPRS or CDMA communication to realize data transmission; it should be noted that only the data transmission diagram of 4 electric energy meters is shown in the figure. When there are multiple watt-hour meters in the station area, the same method can be used for data transmission.

Fig. 3 is the flowchart of data transmission in the electric energy meter of the present invention, and concrete steps are as follows:

Step 1: Set the time interval Δt for data collection;

Step 2: Record the current time t;

Step 3: The temperature sensor and the magnetic field sensing unit start to collect data;

Step 4: Save the data to the storage unit in the energy meter;

Step 5: Set the transmission time interval t _m ;

Step 6: Judging whether t+Δt≤t _m is satisfied, if so, return to step 2; if not, go to step 7;

Step 7: transmit data to external network;

Step 8: Clear the data in the storage unit and return to step 2.

Fig. 4 is a schematic flow chart of the detection method of the electric energy meter of the present invention.

When testing the meter under inspection, the temperature of the meter at a certain period of time and the magnetic induction intensity information of the constant magnetic field are extracted from the main station according to the meter number of the meter under inspection, and the voltage and current data are extracted at the same time; according to the above Information, by controlling the high and low temperature box, constant magnetic field generator and standard power source to simulate the on-site operating environment of the electric energy meter under inspection, and using the standard meter method to obtain the comprehensive error of the meter under inspection.

Figure 5 shows the schematic diagram of the test for simulating the influence of on-site temperature.

As shown in Figure 5, the voltage circuit of the standard meter is connected in parallel with the voltage circuit of the checked meter; the current circuit of the standard meter is connected in series with the current circuit of the checked meter; the pulse ports of the standard meter and the checked meter are connected to the error calculation unit; The error calculation unit calculates the error of the checked meter under this operating condition according to the pulses sent by the pulse port of the checked meter and the standard meter; the checked meter is placed in a high and low temperature box; according to the voltage and Current curve, control the standard power source to output voltage and current test signals in line with the current operating environment; control the high and low temperature box so that the temperature is the reference temperature of 23°C, get the relative error of the tested meter at this time, and record it as α ₁ ; The temperature data of the tested meter in a certain period of time, the temperature in the control high and low temperature box is similar to the on-site operating environment temperature, and the relative error of the checked meter at this time is obtained, which is recorded as α ₂ .

Figure 6 shows the schematic diagram of the experiment for simulating the influence of the field constant magnetic field.

Different from the experiment of simulating the influence of field temperature, the high and low temperature box is replaced by a constant magnetic field generator.

According to the voltage and current curves of the tested meter in a certain period of time, control the standard power source to output voltage and current test signals in line with the current operating environment; according to the data of the constant magnetic field magnetic induction intensity of the tested meter in a certain period of time, control the constant magnetic field The generator produces a constant magnetic field magnetic induction intensity similar to the field operating environment, and the relative error of the checked meter at this time is obtained, which is recorded as α ₃ ; the comprehensive error α of the checked meter can be obtained by the formula get.

The unexplained parts involved in the present invention are the same as the prior art or implemented by adopting the prior art.

Claims (5)

1. a kind of electric energy meter detection method that considers temperature and constant magnetic field joint influence, it is characterized in that, described method is provided with magnetic field induction unit and temperature sensor in electric energy meter; Collect the magnetic induction intensity and the temperature of the constant magnetic field when running on the spot respectively information, and transmit the data in the electric energy meter to the external network; during detection, according to the meter number of the meter under inspection, the information within a certain period of time is extracted from the master station, and the constant magnetic field generator and high and low temperature box are controlled to simulate the on-site operating environment. The laboratory simulates the actual operating environment on site, and obtains the comprehensive error of the tested meter. 2. A kind of electric energy meter detection method that considers temperature and constant magnetic field joint influence according to claim 1, is characterized in that, described electric energy meter comprises: current transformer, first resistor, second resistor, third resistor , temperature sensor, magnetic field sensing unit, A/D converter, DSP, display, storage unit and communication unit; the primary winding of the current transformer is connected to the neutral line N; the secondary winding of the current transformer is connected in parallel with the first resistor , one end is connected to the input end of the A/D converter, and the other end is grounded; the second resistor and the third resistor are connected in series, and are respectively connected to the phase line L and the neutral line N; the common connection end of the third resistor and the second resistor Connect the input end of the A/D converter, and the other end is grounded; the magnetic field sensing unit is installed close to the current transformer and connected to the input end of the A/D converter; the temperature sensor is connected to the input end of the A/D converter; A/D The output end of the D converter is connected with the output end of the DSP; the DSP is also respectively connected with the communication unit, the display and the storage unit. 3. a kind of electric energy meter detection method that considers temperature and constant magnetic field joint influence according to claim 1, it is characterized in that, the data transmission in described electric energy meter is to external network step as follows: (1) Set the time interval Δt of data collection; (2) Record the current time t; (3) The temperature sensor and the magnetic field sensing unit start to collect data; (4) Save the data to the storage unit in the electric energy meter; (5) Set the time interval t _m of transmission; (6) Judging whether t+Δt≤t _m is satisfied, if satisfied, return to step (2); if not satisfied, enter step (7); (7) transmit data to external network; (8) Clear the data in the storage unit and return to step (2). 4. a kind of electric energy meter detection method that takes into account temperature and constant magnetic field joint influence according to claim 1, is characterized in that, the detection method of described electric energy meter is as follows: When a certain electric energy meter running on site is suspected to be faulty, the electric energy meter can be disassembled and used as the inspected meter; according to the meter number information of the inspected meter, the storage unit of the inspected meter is called from the main station to save the temperature, Magnetic induction intensity, voltage and current information with time scale data; according to the above data, the comprehensive error of the tested meter is obtained through the test of simulating the influence of on-site temperature and the test of simulating the influence of on-site constant magnetic field in the laboratory. 5. a kind of watt-hour meter detection method that takes into account temperature and constant magnetic field joint influence according to claim 4, is characterized in that, the comprehensive error test method of described tested meter is as follows: (1) Set up the tested meter test device: the device includes a standard meter, a standard power source, an error calculation unit, a high and low temperature box, and a constant magnetic field generator; the voltage circuit of the standard meter is connected in parallel with the voltage circuit of the tested meter; the standard meter The current circuit of the tested meter is connected in series with the current circuit of the tested meter; the pulse ports of the standard meter and the tested meter are connected to the error calculation unit; Error under operating conditions; (2) In the test of simulating the influence of on-site temperature, the tested meter is placed in a high and low temperature box; according to the voltage and current curve of the tested meter in a certain period of time, the standard power source is controlled to output voltage and current test signals in line with the current operating environment ;Control the high and low temperature box so that the temperature is the reference temperature of 23°C, get l at this time, and record it as α ₁ ; according to the temperature data of the tested meter in a certain period of time, control the temperature in the high and low temperature box and the on-site operating environment Temperature approximation, get the relative error of the tested meter at this time, and record it as α ₂ ; (3) In the test of simulating the influence of the constant magnetic field on site, the tested meter is placed in the constant magnetic field generator, and according to the voltage and current curve of the tested meter in a certain period of time, the standard power source is controlled to output the voltage and current in line with the current operating environment Test signal; according to the constant magnetic field magnetic induction data of the tested meter in a certain period of time, control the constant magnetic field generator to generate a constant magnetic field magnetic induction similar to the field operating environment, and obtain the relative error of the tested meter at this time, and record it as α ₃ ; (4) Calculate the comprehensive error α of the checked meter, the calculation formula of α is as follows: