CN105116364A - Standard measurement unit and method used for electric energy metering remote on-line monitoring system - Google Patents

Abstract

The invention relates to a monitoring system, disclosing a standard measuring unit and a method thereof for a remote online monitoring system of electric energy metering, including a current input card, a voltage input card, a load sampling card, an error calculation card, a motherboard, and a current input card. card, voltage input card, load sampling card, and error calculation card are all connected to the motherboard, and the current input card, voltage input card, load sampling card, and error calculation card are all connected to the motherboard for signal transmission. The input card, voltage input card, load sampling card, and error calculation card input the measurement signal and after signal processing, output the standard electric energy pulse signal through the motherboard. The present invention adopts the secondary circuit measurement method and the pulse comparison method, and realizes standard measurement, error calculation, off-line setting, system calibration and other functions through the error calculation card, so that the monitoring system has strong anti-interference ability and high Reliability, but also greatly improved the measurement accuracy of the monitoring system.

Description

Standard measurement unit and its method for remote on-line monitoring system of electric energy metering

technical field

The invention relates to a monitoring system, in particular to a standard measuring unit used in a remote on-line monitoring system for electric energy metering and a method thereof.

Background technique

Electric energy metering is an important part of the economic work of the electric power industry sector. To ensure the accurate and reliable operation of electric energy metering devices is an important basis for production organization, operation management and leadership decision-making. With the deepening of the reform of the power system, especially after the separation of the power plant and the grid, the technical management requirements for the electric energy metering and monitoring system are getting higher and higher. However, due to the limitation of technical means, especially the measurement unit in the monitoring system, there is still measurement accuracy There are many problems such as low monitoring efficiency, long inspection cycle, and untimely troubleshooting.

The existing standard measurement unit used in the remote on-line monitoring system of electric energy metering mainly has the following problems: first, the measurement unit lacks a secondary loop measurement method, which makes the measurement accuracy low, and ultimately affects the measurement accuracy of the monitoring system; second, the measurement unit lacks measurement Error detection and calculation function, due to real-time changes in the on-site load conditions, the power factor also changes in real time, especially affected by the temporary transient process, the system error is also constantly changing during on-site operation, and the measurement unit lacks error detection and calculation functions. The accuracy of the measurement accuracy is greatly reduced, thereby greatly reducing the measurement accuracy of the monitoring system; the third is that in the case of the main and auxiliary meters installed on site, it cannot meet the simultaneous monitoring and verification of the active or reactive errors of the main and auxiliary meters, which greatly reduces the Monitor system operating efficiency.

Contents of the invention

The present invention aims at the following disadvantages in the existing standard measurement unit used in the remote on-line monitoring system for electric energy metering in the prior art: First, the measurement unit lacks a secondary loop measurement method, which makes the measurement accuracy low, and ultimately affects the measurement accuracy of the monitoring system ; Second, the measurement unit lacks measurement error detection and calculation functions. Due to real-time changes in the on-site load conditions, the power factor also changes in real time, especially affected by the temporary transient process, and the system error is also constantly changing during on-site operation. The measurement unit The lack of error detection and calculation functions greatly reduces the accuracy of the measurement accuracy, thereby greatly reducing the measurement accuracy of the monitoring system; the third is that in the case of the main and auxiliary meters installed on site, it cannot meet the simultaneous monitoring and verification of the active power of the main and auxiliary meters or The reactive power error greatly reduces the operating efficiency of the monitoring system, and provides a standard measurement unit for the remote online monitoring system of electric energy metering that adopts the secondary loop measurement method and has measurement error detection and calculation to greatly improve the measurement accuracy of the system.

In order to solve the above technical problems, the present invention is solved through the following technical solutions:

The standard measurement unit used in the remote on-line monitoring system of electric energy metering, including the current input card, the voltage input card, the load sampling card, the motherboard, the current input card, the voltage input card, and the load sampling card are connected to the motherboard, and also connected to the The error calculation card of the motherboard, the current input card, the voltage input card, the load sampling card, and the error calculation card are all connected to the motherboard for signal transmission, respectively from the current input card, voltage input card, load sampling card, error The calculation card inputs the measurement signal and undergoes signal processing, and then outputs the standard electric energy pulse signal to the standard electric energy pulse output terminal through the motherboard. The current input card, voltage input card, load sampling card, and error calculation card are all equipped with card plugs, and the current input card, voltage input card, load sampling card, and error calculation card are connected to each other through the card plug on the motherboard. Signal transmission.

The standard measurement unit mainly performs remote calibration of the electric energy meter running on-line, real-time on-line monitoring of the characteristic parameters of TA and TV, and judgment on the fault of the secondary circuit.

The monitoring system collects the pulse, voltage and current signals of the online running electric energy meters through multiple channels, and then performs A/D conversion and data processing on the collected signals to realize the verification of multiple online electric energy meters on site. The verification and detection data are stored in the hard disk of the system industrial computer in real time, and the verification data can be read directly on site, or transmitted to the background PC through various remote communication methods, and the background management center can monitor the field power by receiving the data Changes in the accuracy of the meter, so that the faulty energy meter can be dealt with in time.

The monitoring system is tested by connecting the test loops in series to the TA secondary loop and in parallel to the TV secondary loop, which can not only ensure that the current loop will not open, but also ensure that the current sampling will not affect the measurement accuracy of the system. Using 16-bit multi-channel A/D converter, the high-speed digital processing core performs digital signal processing, and controls other electronic circuits to switch between different channels, so as to achieve the purpose of loop testing multiple channels on site or testing specific electric energy meters .

The monitoring system can set the test requirements through the remote background PC, including test requirements and alarm thresholds, and use the data analysis software with friendly and humanized interface for data management, which is convenient for users to realize the modern management of real-time detection data.

Preferably, the voltage input card is provided with a voltage channel switching relay, a function selection relay group, an A/D converter, a CPLD module, and a first microprocessor, and a resistor divider circuit is used between the voltage channel switching relay and the function selection relay group Connection, the function selection relay group is connected with the A/D converter through the program-controlled operational amplifier circuit, the CPLD module is respectively connected with the A/D converter and the first microprocessor, and the CPLD module and the first microprocessor are connected with the error calculation Card connection, the function selection relay group is connected with the current input card and the load sampling card respectively; the first microprocessor controls the CPLD module to output three frequency signals, one output sampling timing signal enters the A/D converter, and one output standard electric energy pulse error The signal is sent to the error calculation card, and the other channel outputs the standard electric energy pulse signal to the standard electric energy pulse output terminal.

As preferably, the error calculation card is provided with a second microprocessor, a standard electric energy pulse error calculation module connected with the second microprocessor, and the second microprocessor is connected with a pulse channel control signal power isolation circuit, pulse power isolation and shaping Circuit, the pulse channel control signal power isolation circuit and the pulse power isolation and shaping circuit are connected with a pulse channel switching circuit, the pulse channel switching circuit is connected with a pulse input protection circuit, the second microprocessor is connected with the voltage input card, and the standard electric energy pulse The error calculation module is connected to the motherboard, and the standard electric energy pulse error signal is output to the standard electric energy pulse error calculation module.

Preferably, the load sampling card is equipped with a CT load voltage sampling module, a current channel switching module, and a voltage channel switching relay. The voltage sampling module is connected to the current channel switching module, and the current channel switching module is connected to the motherboard through a card plug; the first to fourth PT secondary currents are input to the voltage channel switching relay through the input terminal, and the voltage channel switching relay is converted by current-voltage circuit and connects to the motherboard via card plug connections.

Preferably, the current input card is provided with a current transformer and a relay connected to the current transformer, and the relay includes a short-circuit relay and a gating relay connected to the short-circuit relay.

Preferably, the current input card includes a first current input card and a second current input card arranged in parallel, and the first to fifth three-phase current signals and the sixth to tenth three-phase current signals are respectively input to the first Current input card, the second current input card; the first to fourth road meter terminal voltage signal, the first to fourth road PT secondary voltage signal input voltage input card through the input terminal; the first to tenth road main and auxiliary meters have The reactive pulse signal is input to the error calculation card through the input terminal, and the error calculation card is respectively connected to the industrial computer and the reset control box through the interface; the first to fourth PT secondary current signals, the first to tenth CT secondary voltage signals Input the load sampling card through the input terminal; the keyboard is connected to the motherboard.

Preferably, the first to fourth channels of ammeter terminal voltage signals and the first to fourth channels of PT secondary voltage signals are input to the voltage input card in parallel through the input terminals, and the first to fourth channels of ammeter terminal voltage signals pass through the input terminals in sequence through the voltage input card. Channel switching relay, resistance voltage divider circuit, function selection relay group, program-controlled operational amplifier circuit and then input to A/D converter, the first to fourth PT secondary voltage signals pass through the input terminal in turn through the voltage channel switching relay, resistance voltage divider Circuit, function selection relay group, program-controlled op-amp circuit and input A/D converter.

Preferably, the first to fourth PT secondary current signals and the first to tenth CT secondary voltage signals are input to the load sampling card in parallel through the input terminals, and the first to fourth PT secondary current signals are sequentially input through the input terminals After passing through the function selection relay group and the program-controlled operational amplifier circuit, it is input to the A/D converter. The first to tenth CT secondary voltage signals pass through the input terminals in sequence and then enter the A/D converter through the function selection relay group and the program-controlled operational amplifier circuit. .

As a preference, the second microprocessor is connected with the reset control box, the second microprocessor is connected with the industrial computer through the RS232 communication circuit, the second microprocessor is connected with the keyboard through the display drive circuit, and the second microprocessor is respectively connected through the current channel The switching control signal driving circuit and the voltage channel switching control signal driving circuit are connected to the motherboard.

Preferably, a power supply card is also included, the power supply card is used as a power supply, the power supply card is provided with a card plug, and the power supply card is connected to the motherboard through the card plug to realize power supply.

The first current input card, the second current input card, the voltage input card, the error calculation card, the load sampling card, and the power supply card are installed on the rear panel of the chassis to form a board-type installation structure. The input and output signals of the terminals on the rear panel are connected to six boards: the first current input card, the second current input card, the voltage input card, the error calculation card, the load sampling card, and the power supply card. card, voltage input card, error calculation card, load sampling card, and power supply card are respectively connected to the six card slots on the motherboard, and the motherboard plays the role of signal connection between the boards. It also plays the role of fixing each board.

Each current is a three-phase input, with one positive and one negative for each phase. One current transformer is installed for each phase current, and fifteen current transformers are arranged on the first current input card and the second current input card. Each current transformer is switched with two relays, which are functionally divided into short-circuit relays and gating relays, so each current board is equipped with thirty switching relays.

Input 0-5A current from the primary side of the current transformer, and output 0-20mA small current signal from the secondary side, and the control signal output from the error calculation card controls the on-off of the short-circuit relay and the strobe relay; the channel current is gated , the short relay is disconnected, the strobe relay is closed, and the secondary current transformer can output a small current of 0-20mA; the channel current is not strobed, the short relay is closed, the strobe relay is disconnected, and the secondary winding of the current transformer It forms a closed-loop circuit with the short-circuit relay, and the strobe relay is in an open state, and the small current of 0-20mA is not output. The closing of the short-circuit relay is to ensure that the secondary of the current transformer is not opened.

The relay control signals of the two boards of the first current input card and the second current input card are independent. Of the ten currents in the first current input card and the second current input card, only one current at most is always selected.

The load sampling card samples the 30 CT load voltage signals on the ten channel circuit lines on site, and samples the twelve PT load current signals on the four-section bus voltage lines on site, and obtains suitable signals for measurement Select the channel of current and voltage, select a specific channel through the control signal connected by the error calculation card through the motherboard, and then connect the three-phase CT load voltage signal and three-phase PT load current signal of the selected channel to the voltage through the motherboard Enter the card for load measurement calculations.

The voltage input card is provided with a multi-channel A/D converter and a first microprocessor for sampling calculation. The three-phase current signal gated in the current input card is input to the voltage input card, and the CT load sampling voltage signal and PT load sampling current signal in the load sampling card are also input to the voltage input card. The first to fourth voltage input signals of the meter terminal and the first to fourth PT terminal voltage input signals input from the voltage input terminal on the rear panel of the card itself, after the channel control relay is gated, the ammeter terminal is obtained by resistive voltage division. Voltage sampling signal and PT terminal voltage sampling signal. There are five types of three-phase signals that need to be measured. The multi-channel A/D converter can measure up to two types of three-phase signals, which requires signal type selection according to different functions.

When the error calibration function is performed, it is only necessary to measure the standard electric energy at the meter terminal, so only the voltage signal and the three-phase current signal at the three-phase ammeter terminal need to be measured; when the PT secondary voltage drop measurement function is performed, only three-phase measurements are required Meter terminal voltage and three-phase PT terminal voltage are enough; when performing PT load measurement function, only need to measure three-phase PT terminal voltage and three-phase PT load sampling current; when performing CT load measurement function, only need to measure three Phase CT load sampling voltage and three-phase current are sufficient.

The two program-controlled operational amplifier circuits in the voltage input card circuit perform program-controlled amplification on the gating signals of the two channel groups respectively.

The voltage channel switching relay is responsible for switching between the four input voltages of the ammeter terminal and the input voltage of the four PT terminals.

The resistance voltage divider circuit performs resistance division sampling for the input voltage of the meter terminal and the input voltage of the PT terminal respectively.

The CPLD module completes the generation of the sampling timing signal of the A/D converter and the output of two electric energy pulses.

The first microprocessor is responsible for sampling calculation and data processing.

The error calculation card is responsible for multi-channel pulse input and voltage, current and pulse channel switching, standard pulse input, error calculation, communication with the voltage input card, control of the reset control box, and communication with the industrial computer.

The main components of the pulse input protection circuit are TVS tubes and current limiters, which are connected to the pulse input terminals on the rear panel to prevent damage to the circuit board components when the high-voltage signal is connected, and protect the internal circuit of the circuit board.

The function of the pulse channel switching circuit is to switch channels of multiple pulse signals passing through the pulse input protection circuit. Its control signal comes from the signal after the second microprocessor pin passes through the power isolation circuit.

The display driving circuit is used to drive the display data lines of the liquid crystal display.

The current channel switching control signal driving circuit plays the role of driving the current channel control signal, and its control signal line is connected to the first current input card and the second current input card.

The voltage channel switching control signal driving circuit plays a role in driving the voltage channel control signal, and its control signal line is connected to the voltage input card and the load sampling card.

The second microprocessor is responsible for calculating the electric energy error, sending channel switching signals of voltage, current and pulse, and communicating with the industrial computer.

The pulse power isolation and shaping circuit is used for power isolation and waveform shaping of the pulse signal.

The RS232 communication circuit is connected to the communication port of the industrial computer for communication with the industrial computer.

The key device on the power card is composed of two switching power supplies and a filter. One switching power supply provides the working power of the circuit: +5V and ±15V, and the other switching power supply provides the switching coil power of the relay: +24V.

The power lines supply power to each board through the card plug and through the motherboard.

The standard measurement method used in the remote on-line monitoring system of electric energy metering includes the error calculation method, the error calculation method adopts the pulse comparison method, and the relative error calculation formula of the pulse comparison method is:

in: The measured pulse number is the standard pulse number of the tested electric energy meter (4) pulse measured according to the set number of turns; the calculation formulas of the voltage, current and active power of N sampling points in one cycle are respectively and Among them, P _i and P _u are the sampling points of current and voltage respectively, and K is the correction coefficient.

The error test method is: connect the input voltage of the field energy meter in parallel to the voltage input terminal of the meter terminal of the corresponding channel of the standard measurement unit, and connect the input current in series to the current input terminal of the corresponding channel of the standard measurement unit, and connect the active and reactive power of the energy meter to the corresponding channel of the standard measurement unit. The power pulse is connected to the pulse input terminal of the corresponding channel of the standard measurement unit; the standard measurement unit controls the channel switching switch, switches the voltage bus and current channel, and switches the monitored object to the corresponding electric energy meter; the front end of the ADC sampling circuit in the standard measurement unit also There is a group of function switching switches. When the error test is performed, the function switching switches switch the signals on the six input channels of the A/D converter into three-phase ammeter terminal voltage and three-phase current signals; the sampled and calculated signals in the standard measurement unit The input signal is the voltage and current signal of the monitored electric energy meter, so that its standard voltage, current, active power and reactive power parameters can be measured, and the standard active pulse or reactive pulse is output; the error calculation card receives the standard electric energy at the same time The pulse and the electric energy pulse of the tested meter are used to calculate the electric energy error of the checked meter by using the pulse comparison method.

The PT secondary voltage drop test method is: connect the voltage signal of the PT secondary side to the PT terminal voltage input terminal of the corresponding channel of the standard measurement unit through the voltage dedicated line, and add the voltage signal of the meter terminal that has been connected; the standard measurement unit controls The channel switching switch switches the voltage bus to the monitored PT line; the function switching switch switches the signals on the six input channels of the A/D converter into three-phase meter terminal voltage and three-phase PT terminal voltage, using Fourier Calculation formula, at the same time calculate the effective value and initial phase angle of the three-phase meter terminal voltage and three-phase PT terminal voltage, and obtain the ratio difference and angle difference of the PT secondary circuit.

The PT secondary load test method is: install a special through-the-center CT on the voltage line of the PT secondary side, obtain the current signal of the PT secondary circuit, connect it to the PT secondary current input terminal of the corresponding channel of the standard measurement unit, and add The voltage signal on the secondary side of the PT that has been connected; the standard measurement unit controls the channel switch to switch the voltage bus to the monitored PT line; the function switch switches the signals on the six input channels of the A/D converter to The three-phase PT secondary voltage signal and the three-phase PT secondary current signal measure the load on the secondary side of the PT.

The CT secondary load test method is: Connect the voltage of the CT secondary side to the CT secondary voltage input terminal of the corresponding channel of the standard measurement unit with a dedicated line, and add the current signal of the connected CT secondary side; the standard measurement unit Control the channel switching switch to switch the current channel to the monitored CT line; the function switching switch switches the signals on the six input channels of the A/D converter into three-phase CT secondary voltage signals and three-phase CT secondary current signals , to measure the load on the secondary side of the CT.

This patent adopts a high-precision standard measurement unit, and all the measured pulses of a group of electric energy meters are introduced into the pulse port on site, and compared with the standard electric energy pulses inside the standard measurement unit, so as to calculate the error of the electric energy meter.

Since the monitoring system works under the test mode of a group of electric energy meters, a multi-way switch is set inside the system, and the user switches to the corresponding circuit for testing at different times, and the microprocessor is responsible for the control and calculation tasks. After the multi-channel voltage and current of the measured electric energy meter are introduced into the monitoring system, the multi-channel switch is responsible for switching. The switching is directly managed by the microprocessor. The user can store the preset information in the memory through the preset time and control sequence. Internally, the automatic cycle test is realized to ensure that the whole test process is in order, so that the standard meter can collect the voltage, current and pulse signal of the corresponding loop at the same time.

TV secondary circuit voltage drop test: For the TV secondary circuit voltage drop test, it is necessary to lead out a dedicated line from the TV secondary side to connect to the monitoring system. Since the monitoring system is a high-impedance unit inside, the voltage generated on the dedicated line is negligible. The voltage of the monitoring system is connected as the voltage of the secondary terminal of the TV, and then compared with the voltage of the electric energy meter terminal, the ratio difference and angle difference of the voltage are calculated. Since most of the actual lines use the busbar TV, multiple watt-hour meters can share a set of TV. For the test of the voltage drop of the TV secondary circuit, the busbar TV is used as the unit, and it is not necessary to introduce all the voltage drop lines for each meter. The voltage drop test of the TV secondary circuit needs to be carried out synchronously with the collection of the terminal voltage of the electric energy meter, and directly compared with the TV secondary terminal voltage to calculate the corresponding parameters, such as angle difference and ratio difference.

Load test of the TV secondary circuit: In addition to the need to lead the voltage line from the TV secondary side to the monitoring system, it is also necessary to use a special through-hole current transformer to obtain the current on the TV secondary side voltage line and connect it to the monitoring system. For the convenience of installation, the special feed-through current transformer needs to adopt the open type CT. The layout of the voltage dedicated line just meets the needs of the TV secondary voltage drop test. With the voltage and current of the TV secondary circuit, it is simple to calculate its load.

Load test of the TA secondary circuit: It is necessary to lead out a dedicated voltage line from the TA secondary side to connect to the monitoring system. The higher the voltage of the TA secondary side, the heavier the TA secondary load. The access of this voltage, together with the series input of the current circuit of the electric energy meter, can calculate the load of the TA secondary circuit.

This patent has the following advantages:

The combined test method of standard measurement unit and industrial computer is adopted. The standard measurement unit is easy to disassemble and send for inspection, while the industrial computer is very convenient to operate as a man-machine interface, and its hard disk has a large storage space, and the design of the reset control box can effectively avoid The communication interruption caused by the crash of the industrial computer is eliminated.

Using 16-bit multi-channel A/D converter for synchronous high-precision sampling, high-performance 32-bit microprocessor, core frequency up to 120MHz, data channel transmission rate up to 200kSPS, current transformer adopts active compensation current transformer, with flexible Programmable operational amplifier, to achieve measurement accuracy of 0.05.

The voltage loop is connected in parallel with the terminals of the energy meter. In order to prevent the voltage loop of the monitoring system from affecting the normal collection of the terminal voltage of the energy meter, the voltage loop circuit inside the system is designed as a high-impedance input to ensure that no overcurrent or short circuit occurs.

In order to prevent the monitoring system terminal current loop from affecting the smooth flow of the TA secondary loop, each current in the monitoring system uses a high-precision through-the-center CT to ensure that neither the signal acquisition nor the multi-channel switch will cause the danger of the TA secondary loop opening .

Since the pulse transmission line may be subject to strong magnetic interference from the substation, resulting in signal distortion, especially when the pulse constant is too high, it is more susceptible to interference. Therefore, the monitoring system designs pulse shaping in the pulse input circuit, which effectively prevents false pulse signals caused by interference.

For the situation where the main and auxiliary meters are installed on site, the active and reactive four-way pulses of the main and auxiliary electric energy meters on the same current circuit are specially designed to be input to the monitoring system at the same time, and the active or reactive energy of the two electric energy meters can be verified at the same time. power error.

The cycle test data in the monitoring system will be automatically saved to the hard disk of the industrial computer. The data is stored in a group format. The saved data can be queried according to the record number, and can also be uploaded to the background management center through Ethernet or GPRS communication. In addition, setting parameters, such as wiring mode, label, electric energy constant, alarm parameters, etc., can also be transmitted to the monitoring unit through the background management center. When measuring pressure drop, load and error data, the monitoring system will automatically call the set threshold to compare with the measured parameters. When the threshold is exceeded, the system will automatically trigger an alarm pulse to realize call back or store the alarm information in the alarm Information memory, the background management system can query whether there is alarm information in real time.

Due to the adoption of the above technical scheme, the present invention has remarkable technical effects: it adopts the secondary circuit measurement method and the pulse comparison method, and realizes multiple functions such as standard measurement, error calculation, off-line setting, and system calibration through the error calculation card, so that The monitoring system has strong anti-interference ability and high reliability, and also greatly improves the measurement accuracy of the monitoring system.

Description of drawings

Fig. 1 is a functional block diagram of an embodiment of a standard measurement unit used in a remote on-line monitoring system for electric energy metering according to the present invention.

Fig. 2 is a functional block diagram of an embodiment of the voltage input card of the present invention.

Fig. 3 is a functional block diagram of an embodiment of the error calculation card of the present invention.

Fig. 4 is a schematic structural diagram of an embodiment of a voltage input card of the present invention.

Fig. 5 is a schematic structural diagram of an embodiment of an error calculation card according to the present invention.

Fig. 6 is a schematic structural diagram of an embodiment of a load sampling card of the present invention.

Fig. 7 is a schematic structural diagram of an embodiment of the current input card of the present invention.

The names of the parts indicated by the numbers in the drawings are as follows: 1-keyboard, 2-standard electric energy pulse output terminal, 3-motherboard, 4-card plug, 5-current input card, 6-input terminal, 7-voltage Input card, 8-reset control box, 9-industrial computer, 10-error calculation card, 11-load sampling card, 12-power supply card, 13-voltage channel switching relay, 14-resistance voltage divider circuit, 15-function selection relay Group, 16-program-controlled operational amplifier circuit, 17-A/D converter, 18-CPLD module, 19-first microprocessor, 20-standard energy pulse error calculation module, 21-RS232 communication circuit, 22-pulse input protection Circuit, 23-pulse power isolation and shaping circuit, 24-pulse channel switching circuit, 25-pulse channel control signal power isolation circuit, 26-second microprocessor, 27-display drive circuit, 28-current channel switching control signal drive Circuit, 29-voltage channel switching control signal drive circuit, 30-CT load voltage sampling module, 31-current channel switching module, 32-current-voltage conversion circuit, 33-current transformer, 34-relay, 51-first current Input card, 52—the second current input card.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

Example 1

The standard measurement unit used in the remote online monitoring system for electric energy metering, as shown in Figure 1-7, includes a current input card 5, a voltage input card 7, a load sampling card 11, a motherboard, a current input card 5, a voltage input card 7, The load sampling card 11 is all connected to the motherboard 3, and also includes an error calculation card 10 connected to the motherboard 3, the current input card 5, the voltage input card 7, the load sampling card 11, and the error calculation card 10 are all connected to the motherboard 3. The board 3 is connected for signal transmission, respectively input measurement signals from the current input card 5, voltage input card 7, load sampling card 11, and error calculation card 10, and after signal processing, the standard electric energy pulse signal is output through the motherboard 3 to the standard electric energy pulse Output terminal 2. The current input card 5, the voltage input card 7, the load sampling card 11, and the error calculation card 10 are all provided with a card plug 4, and the current input card 5, the voltage input card 7, the load sampling card 11, and the error calculation card 10 are all passed through each other. It is connected with the card plug 4 on the motherboard 3 for signal transmission.

The voltage input card 7 is provided with a voltage channel switching relay 13, a function selection relay group 15, an A/D converter 17, a CPLD module 18, a first microprocessor 19, and between the voltage channel switching relay 13 and the function selection relay group 15 Connected by the resistor divider circuit 14, the function selection relay group 15 is connected with the A/D converter 17 by the program-controlled operational amplifier circuit 16, and the CPLD module 18 is connected with the A/D converter 17 and the first microprocessor 19 respectively, The CPLD module 18 and the first microprocessor 19 are all connected with the error calculation card 10, and the function selection relay group 15 is connected with the current input card 5 and the load sampling card 11 respectively; the first microprocessor 19 controls the CPLD module 18 to output three-way frequency Signal, one output sampling timing signal into A/D converter 17, one output standard electric energy pulse error signal to error calculation card 10, the other output standard electric energy pulse signal to standard electric energy pulse output terminal 2.

The error calculation card 10 is provided with a second microprocessor 26, a standard electric energy pulse error calculation module 20 connected with the second microprocessor 26, and the second microprocessor 26 is connected with a pulse channel control signal power supply isolation circuit 25, a pulse power supply Isolation and shaping circuit 23, pulse channel control signal power isolation circuit 25 and pulse power isolation and shaping circuit 23 are connected with pulse channel switching circuit 24, pulse channel switching circuit 24 is connected with pulse input protection circuit 22, the second microprocessor 26 is connected to the voltage input card 7 , the standard electric energy pulse error calculation module 20 is connected to the motherboard 3 , and the standard electric energy pulse error signal is output to the standard electric energy pulse error calculation module 20 .

The load sampling card 11 is equipped with a CT load voltage sampling module 30, a current channel switching module 31, and a voltage channel switching relay 13. The first to tenth CT secondary voltages are input to thirty CT load voltage sampling modules 30 through the input terminals. The CT load voltage sampling module 30 is connected to the current channel switching module 31, and the current channel switching module 31 is connected to the motherboard 3 through the card plug 4; the first to fourth PT secondary currents input the voltage channel switching relay 13 through the input terminal 6, The voltage channel switching relay 13 is connected to the motherboard 3 through the current-voltage conversion circuit 32 and through the card plug 4 .

The current input card 5 is provided with a current transformer 33 and a relay 34 connected with the current transformer 33, and the relay 34 includes a short relay and a gating relay connected with the short relay.

The current input card 5 includes a first current input card 51 and a second current input card 52 arranged in parallel, and the first to fifth three-phase current signals and the sixth to tenth three-phase current signals are respectively input into the first to fifth three-phase current signals through the input terminal 6. A current input card 51, a second current input card 52; the first to fourth road meter terminal voltage signals, and the first to fourth road PT secondary voltage signals are input to the voltage input card 7 through the input terminal 6; the first to tenth roads The reactive pulse signal of the main and auxiliary meters of the road is input to the error calculation card 10 through the input terminal 6, and the error calculation card 10 is respectively connected to the industrial computer 9 and the reset control box 8 through the interface; the first to fourth PT secondary current signals, the second The first to tenth CT secondary voltage signals are input to the load sampling card 11 through the input terminal 6 ; the keyboard 1 is connected to the motherboard 3 .

The first to fourth channels of ammeter terminal voltage signals and the first to fourth channels of PT secondary voltage signals are input to the voltage input card 7 in parallel through the input terminal 6, and the first to fourth channels of ammeter terminal voltage signals pass through the input terminals 6 in turn through the voltage input card 7. Channel switching relay 13, resistance voltage divider circuit 14, function selection relay group 15, program-controlled operational amplifier circuit 16 are input to A/D converter 17, and the first to fourth PT secondary voltage signals pass through the input terminal 6 through the voltage channel in turn After switching the relay 13, the resistance voltage divider circuit 14, the function selection relay group 15, and the program-controlled operational amplifier circuit 16, the A/D converter 17 is input.

The first to fourth PT secondary current signals and the first to tenth CT secondary voltage signals are input to the load sampling card 11 in parallel through the input terminal 6, and the first to fourth PT secondary current signals are sequentially input through the input terminal 6 After passing through the function selection relay group 15 and the program-controlled operational amplifier circuit 16, it is input to the A/D converter 17, and the first to tenth road CT secondary voltage signals pass through the input terminal 6 and then pass through the function selection relay group 15 and the program-controlled operational amplifier circuit 16 in turn. The A/D converter 17 is input.

The second microprocessor 26 is connected with the reset control box 8, the second microprocessor 26 is connected with the industrial computer 9 through the RS232 communication circuit 21, the second microprocessor 26 is connected with the keyboard 1 through the display drive circuit 27, and the second microprocessor The device 26 is connected to the motherboard 3 through the current channel switching control signal driving circuit 28 and the voltage channel switching control signal driving circuit 29 respectively.

Also includes a power card 12, the power card 12 is used as a power supply, the power card 12 is provided with a card plug 4, and the power card 12 is connected to the motherboard 3 through the card plug 4 to realize power supply.

The standard measurement method used in the remote on-line monitoring system of electric energy metering includes the error calculation method, the error calculation method adopts the pulse comparison method, and the relative error calculation formula of the pulse comparison method is:

in: The measured pulse number is the standard pulse number of the tested electric energy meter (4) pulse measured according to the set number of turns; the calculation formulas of the voltage, current and active power of N sampling points in one cycle are respectively and Among them, P _i and P _u are the sampling points of current and voltage respectively, and K is the correction coefficient.

In a word, the above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the patent of the present invention.

Claims (10)

1. The standard measurement unit used in the remote online monitoring system of electric energy metering, including current input card (5), voltage input card (7), load sampling card (11), motherboard (3), current input card (5), The voltage input card (7), the load sampling card (11) are all connected to the motherboard (3), and it is characterized in that: it also includes an error calculation card (10) connected to the motherboard (3), a current input card (5), The voltage input card (7), the load sampling card (11), and the error calculation card (10) are all connected to the motherboard (3) for signal transmission, respectively from the current input card (5), the voltage input card (7) ), the load sampling card (11), and the error calculation card (10) input the measurement signal and undergo signal processing, and then output the standard electric energy pulse signal to the standard electric energy pulse output terminal (2) through the motherboard (3). 2. The standard measuring unit for the remote on-line monitoring system of electric energy metering according to claim 1, characterized in that: the voltage input card (7) is provided with a voltage channel switching relay (13), a function selection relay group (15) , A/D converter (17), CPLD module (18), first microprocessor (19), voltage channel switching relay (13) and function selection relay group (15) through resistance divider circuit (14) Connection, the function selection relay group (15) and the A/D converter (17) are connected by a program-controlled operational amplifier circuit (16), and the CPLD module (18) is respectively connected with the A/D converter (17), the first microprocessor device (19), the CPLD module (18), the first microprocessor (19) are all connected with the error calculation card (10), and the function selection relay group (15) is respectively connected with the current input card (5), the load sampling card ( 11) connection; the first microprocessor (19) controls the CPLD module (18) to output three-way frequency signals, one-way output sampling timing signal enters A/D converter (17), and one-way output standard electric energy pulse error signal to error calculation card (10), and the other channel outputs the standard electric energy pulse signal to the standard electric energy pulse output terminal (2). 3. The standard measuring unit for the remote on-line monitoring system of electric energy metering according to claim 1, characterized in that: the error calculation card (10) is provided with a second microprocessor (26) and a second microprocessor (26) connected standard electric energy pulse error calculation module (20), the second microprocessor (26) is connected with pulse channel control signal power supply isolation circuit (25), pulse power supply isolation and shaping circuit (23), pulse channel control signal A pulse channel switching circuit (24) is connected between the power isolation circuit (25) and the pulse power isolation and shaping circuit (23), the pulse channel switching circuit (24) is connected with a pulse input protection circuit (22), and the second microprocessor (26) is connected with the voltage input card (7), the standard electric energy pulse error calculation module (20) is connected with the motherboard (3), and the standard electric energy pulse error signal is output to the standard electric energy pulse error calculation module (20). 4. The standard measuring unit for the remote on-line monitoring system of electric energy metering according to claim 1, characterized in that: the load sampling card (11) is provided with a CT load voltage sampling module (30), a current channel switching module (31 ), a voltage channel switching relay (13), the first to tenth CT secondary voltages are input to thirty CT load voltage sampling modules (30) through input terminals, and the CT load voltage sampling module (30) and the current channel switching module ( 31) connection, the current channel switching module (31) is connected to the motherboard (3) through the card plug (4); the first to fourth PT secondary currents are input to the voltage channel switching relay (13) through the input terminal (6), The voltage channel switching relay (13) is connected to the motherboard (3) through the current-voltage conversion circuit (32) and through the card plug (4). 5. The standard measurement unit for electric energy metering remote on-line monitoring system according to claim 1, characterized in that: the current input card (5) includes a first current input card (51) and a second current input card arranged in parallel (52), the first to fifth three-phase current signals and the sixth to tenth three-phase current signals are respectively input into the first current input card (51) and the second current input card (52) through the input terminal (6) ;The first to fourth road meter terminal voltage signals and the first to fourth road PT secondary voltage signals are input to the voltage input card (7) through the input terminal (6); the first to tenth road main and auxiliary meters have reactive pulses The signal is input to the error calculation card (10) through the input terminal (6), and the error calculation card (10) is respectively connected to the industrial computer (9) and the reset control box (8) through the interface; the first to fourth PT secondary current signals . The first to tenth CT secondary voltage signals are input to the load sampling card (11) through the input terminal (6); the motherboard (3) is connected with a keyboard (1). 6. The standard measurement unit for the remote on-line monitoring system of electric energy metering according to claim 2, characterized in that: the first to fourth road meter terminal voltage signals, the first to fourth road PT secondary voltage signals are input The terminals (6) input the voltage input card (7) in parallel, and the voltage signals of the first to fourth meter terminals pass through the input terminals (6) and pass through the voltage channel switching relay (13), the resistance voltage divider circuit (14), and the function selection relay in sequence group (15), the program-controlled operational amplifier circuit (16) and then input the A/D converter (17), and the first to fourth PT secondary voltage signals pass through the input terminal (6) in turn through the voltage channel switching relay (13), Resistor voltage divider circuit (14), function selection relay group (15), program-controlled op-amp circuit (16) are input into A/D converter (17). 7. The standard measurement unit for the remote on-line monitoring system of electric energy metering according to claim 4, characterized in that: the first to fourth PT secondary current signals, the first to tenth CT secondary voltage signals pass through The input terminal (6) is input in parallel to the load sampling card (11), and the first to fourth PT secondary current signals are input through the input terminal (6) through the function selection relay group (15) and the program-controlled operational amplifier circuit (16) in turn. A/D converter (17), the first to tenth CT secondary voltage signals are input to the A/D converter after passing through the input terminal (6) in turn through the function selection relay group (15) and the program-controlled operational amplifier circuit (16) (17). 8. The standard measurement unit for electric energy metering remote on-line monitoring system according to claim 3, characterized in that: the second microprocessor (26) is connected with the reset control box (8), and the second microprocessor (26) ) is connected with the industrial computer (9) through the RS232 communication circuit (21), the second microprocessor (26) is connected with the keyboard (1) through the display drive circuit (27), and the second microprocessor (26) is respectively passed through the current channel The switching control signal driving circuit (28) and the voltage channel switching control signal driving circuit (29) are connected to the motherboard (3). 9. The standard measuring unit for the remote on-line monitoring system of electric energy metering according to claim 1, characterized in that: it also includes a power supply card (12), the power supply card (12) is used as a power supply, and the power supply card (12) is provided with There is a card plug (4), and the power supply card (12) is connected to the motherboard (3) through the card plug (4) to realize power supply. 10. The standard measurement method for the remote on-line monitoring system of electric energy metering, characterized in that it includes an error calculation method, the error calculation method adopts the pulse comparison method, and the relative error calculation formula of the pulse comparison method is: in: The measured pulse number is the standard pulse number of the tested electric energy meter (4) pulse measured according to the set number of turns; the calculation formulas of the voltage, current and active power of N sampling points in one cycle are respectively and Among them, P _i and P _u are the sampling points of current and voltage respectively, and K is the correction coefficient.