CN203433104U - Real load error detector for secondary electric-energy metering loop of intelligent transformer station - Google Patents

Abstract

The utility model discloses a real load error detection device for a secondary circuit of electric energy measurement in an intelligent substation. The real load error detection device includes a data acquisition circuit connected in sequence, a dual-port RAM, a DSP processor, a single-chip microcomputer, and a traditional voltage for live operation of the intelligent substation. , The secondary output of the current transformer real-time voltage and current signals are simultaneously input to the secondary circuit of the detected electric energy metering and the actual load on-site verification device, and at the same time the electric energy pulse of the digital electric energy meter in the secondary circuit of the electric energy metering is also input to the actual load site The calibration device compares the electric energy measured by the secondary circuit of electric energy measurement with the electric energy measured by the actual load on-site calibration device, and obtains the error, so as to realize the overall detection of the actual load of the secondary circuit of electric energy measurement in the smart substation. The utility model solves the problem of overall detection of the actual load of the secondary circuit of electric energy metering when the intelligent substation is running with electricity, and the detection device has high economy, reliability and safety.

Description

Intelligent substation electric energy metering secondary circuit actual load error detection device

technical field

The utility model relates to the technical field of electric energy metering device verification when an intelligent substation is running with load in an intelligent grid, in particular to a real load error detection device for a secondary circuit of an electric energy metering secondary circuit of an intelligent substation. the

Background technique

At present, China's smart grid has entered a period of rapid development, and many new smart substations of various voltage levels have been newly built in China. At this time, compared with traditional substations, the power metering mode of smart substations has undergone a qualitative change. The secondary circuit of power metering The composition and working methods have also changed. The electric energy metering system in a traditional substation consists of electromagnetic current transformers, electromagnetic voltage transformers, capacitive voltage transformers, electric energy meters and secondary connecting cables. It consists of secondary cables and traditional electric energy meters.

There are two main modes of electric energy metering in smart substations. The first mode is an all-digital mode, and the signals transmitted from primary equipment, secondary equipment and their transmission circuits are all digital. The digital signals output by the electrical unit boxes of electronic voltage transformers and current transformers are respectively transmitted to the voltage and current merging units through optical fibers, and the merging unit transmits the digital signals to the network switch. The network switch transmits the digital signal conforming to the IEC61850-9-2LE communication protocol to the digital energy meter through the optical fiber. Although this mode is highly digitalized and intelligent, the long-term stability and reliability of electronic voltage transformers and current transformers have yet to be tested, and the failure rate is high, so another smart substation energy metering mode has emerged. . The second mode is a mixed form of analog and digital. The voltage transformer is a traditional electromagnetic or capacitive type, and the current transformer is an electromagnetic type. The voltage and current analog signals output by the traditional transformer are respectively connected to the belt mode through cables. The voltage and current merging unit of the digital converter, the merging unit outputs a digital signal conforming to the IEC61850-9-2LE communication protocol, and transmits it to the digital electric energy meter through the optical fiber, and the digital electric energy meter performs electric energy measurement. The utility model is mainly aimed at the creation of the utility model for the second electric energy metering mode of the intelligent substation.

Because the electric energy metering mode of the substation has changed, the composition and working mode of the electric energy metering secondary circuit have also changed. The secondary circuit of electric energy metering in traditional substations is mainly composed of secondary signal transmission cables of traditional current/voltage transformers and conventional electric energy meters; while the secondary circuit of electric energy metering in the second electric energy metering mode of smart substations is mainly composed of analog-to-digital converters It is composed of voltage/current merging unit, optical fiber and digital electric energy meter. The accuracy of the entire electric energy metering secondary circuit has a great influence on the accuracy of the electric quantity. The traditional substation electric energy metering secondary circuit can be judged by measuring the secondary voltage drop of the voltage transformer under the condition of real load and the secondary load of the entire secondary circuit. Whether its accuracy level meets the regulations to ensure the fairness and justice of electric energy measurement. However, the structure and working mechanism of the secondary circuit of electric energy metering in smart substations are different from those of traditional substations. The error detection method of the secondary circuit of electric energy metering in traditional substations is no longer applicable when the secondary circuit of electric energy metering in smart substations is operating with load. error detection. At present, by consulting domestic and foreign literature, there is no report on the overall error detection of the actual load of the secondary circuit of the smart substation electric energy metering. the

Contents of the invention

The technical problem to be solved by the utility model is to provide an intelligent substation electric energy metering secondary circuit actual load error detection device to meet the overall error detection of the electric energy metering secondary circuit actual load error detection when the intelligent substation is live. .

In order to solve the above-mentioned technical problems, the technical solution adopted by the utility model is: a device for detecting actual load errors of the secondary circuit of electric energy metering in intelligent substations, including sequentially connected data acquisition circuits, dual-port RAM, DSP processors, and single-chip microcomputers. The dual-port RAM is connected to the signal processing circuit, and the signal processing circuit is connected to the photoelectric pulse receiving module; the DSP processor and the single-chip microcomputer are connected to the power supply module; The voltage joint junction box and the three-phase current joint junction box are connected; the photoelectric pulse receiving module is connected with the digital electric energy meter of the secondary circuit of the electric energy measurement of the intelligent substation.

As a preferred solution, the DSP processor is connected with an external memory.

As a preferred solution, the single-chip microcomputer is connected with a keyboard, a liquid crystal display, a printer, a USB interface, and a network interface.

As a preferred solution, the single-chip microcomputer is connected with the upper computer through a communication interface.

As a preferred solution, the model of the DSP processor is TMS320F2812.

As a preferred solution, the model of the single-chip microcomputer is 80C196.

；实负荷现场校验装置利用从三相电压联合接线盒、三相电流联合接线盒处得到的三相电压、三相电流模拟量计算出实际运行时的电能

，即标准电能值；实负荷现场校验装置对

和

进行比较，计算出被检测电能计量二次回路的整体电能计量误差，完成对电能计量二次回路的整体误差检测。 The actual load error detection method of the utility model is as follows: the voltage merging unit converts the three-phase voltages U _a , U _b , U _c into digital messages in FT3 format, and the current merging unit converts the three-phase currents I _a , I _b , I _c Converted into digital current signal, the current merging unit converts the digital message and digital current signal in FT3 format into IEC61850-9-2LE format message, and transmits it to the network switch through optical fiber, and then the network switch transmits the digital message through optical fiber To the digital electric energy meter, the electric energy under the actual load condition is calculated by the digital electric energy meter

; The actual load on-site verification device uses the three-phase voltage and three-phase current analogs obtained from the three-phase voltage joint junction box and the three-phase current joint junction box to calculate the actual operating electric energy

, that is, the standard electric energy value; the actual load on-site calibration device is

and

By comparison, the overall electric energy measurement error of the detected electric energy metering secondary circuit is calculated, and the overall error detection of the electric energy metering secondary circuit is completed.

的计算公式为： Energy metering error

The calculation formula is:

,

，N为脉冲数，C为数字式电能表常数。 in,

, N is the number of pulses, and C is the constant of the digital electric energy meter.

Compared with the prior art, the utility model has the beneficial effects as follows: the device structure of the utility model is simple; the utility model proposes a real An overall error detection device for the secondary circuit of electric energy metering in smart substations under load. Using this device, the calibration personnel can perform the calibration without any electrical contact with the primary high-voltage circuit, and can also perform the calibration without powering off the primary equipment and the normal live operation of the secondary equipment. It solves the problem of overall detection and verification of the secondary circuit of electric energy metering with actual load when the smart substation is not powered off, and the device of the utility model has the advantages of safety and high efficiency.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the electric energy metering secondary circuit and the actual load on-site verification device according to an embodiment of the present invention;

Fig. 2 is a schematic structural diagram of a real load on-site verification device according to an embodiment of the present invention.

Detailed ways

。数字电能表计量的电能值

不仅可以反映被试电压合并单元和电流合并单元的误差，还可以反映数字电能表本身的计量误差，因此，本实用新型提出的方法可以检测电能计量二次回路运行在实负荷工况下的整体误差。同时，实负荷现场校验装置使用由电压、电流联合接线盒处得到的三相电压、电流模拟量计算得出实际负荷的电能值，即标准电能值

。数字式电能表的输出脉冲被传送到实负荷现场校验装置，并由实负荷现场校验装置把

与

进行比较，计算出电能计量二次回路实负荷下的有功、无功计量误差，完成对智能变电站带电运行时电能计量二次回路实负荷下的整体误差检测。误差计算公式为： As shown in Figure 1, bus I and bus II of the smart substation operate with live electricity, traditional electromagnetic or capacitive voltage transformers are connected to the busbars through the isolation switch QS, and their secondary output three-phase voltages U _a , U _b , U _c pass through the cables Connect to the three-phase voltage joint junction box through the circuit breaker. The three-phase voltage signal is divided into two paths at the voltage joint junction box, one path is sent to the voltage merging unit with an analog-to-digital converter, and the other path is connected to the actual load on-site verification device. The traditional electromagnetic current transformer is also connected to the busbar through the isolating switch QS, and its secondary output three-phase current I _a , I _b , I _c are directly connected to the three-phase current joint junction box through the cable, and then connected to the analog-to-digital converter At the same time, the current input terminal of the real load field verification device is connected in series with the three-phase current circuit at the current joint junction box. The three-phase voltages U _a , U _b , U _c are converted into digital messages in FT3 format by the voltage merging unit, and then transmitted to the current merging unit with an analog-to-digital converter via optical fiber. The three-phase currents I _a , I _b , and I _c are converted into digital quantities by the current merging unit, and the current merging unit also converts the voltage digital signal and digital current signal in FT3 format into IEC61850-9-2LE format messages, and transmits them through the optical fiber It is transmitted to the network switch, and then the network switch transmits the digital message to the digital electric energy meter through the optical fiber, and the digital electric energy meter calculates the electric energy under the real load condition

. Electric energy value measured by digital electric energy meter

It can not only reflect the error of the tested voltage combining unit and the current combining unit, but also reflect the measurement error of the digital electric energy meter itself. Therefore, the method proposed by the utility model can detect the overall performance of the secondary circuit of electric energy measurement under the actual load condition. error. At the same time, the actual load on-site verification device uses the three-phase voltage and current analog quantities obtained from the voltage and current joint junction box to calculate the actual load energy value, that is, the standard energy value

. The output pulse of the digital electric energy meter is transmitted to the actual load on-site verification device, and the actual load on-site verification device

and

By comparison, the active and reactive power measurement errors under the real load of the secondary circuit of electric energy metering are calculated, and the overall error detection of the secondary circuit of electric energy metering under the real load of the smart substation is completed when the smart substation is running live. The error calculation formula is:

     （1）

(1)

(2)

Putting (2) into (1), we get:

    （3）

(3)

In formula (3), N is the number of pulses, and C is the constant of the digital electric energy meter.

As shown in Figure 2, the real-load on-site verification device mainly includes: data acquisition circuit (main chip ADS1210), dual-port RAM storage module, signal processing circuit (mainly RC filter circuit), photoelectric pulse receiving module (mainly composed of PNP tube and resistance connection), external memory, power supply module, liquid crystal display module, keyboard input module, communication module, network interface, USB interface, printing module, DSP control system and single-chip processing system. DSP control system is mainly connected with dual-port RAM storage module, external memory and single-chip processing system. The single-chip processing system is mainly connected with the liquid crystal display module, the keyboard input module, the communication module, the network interface, the USB interface and the printing module. The DSP control system mainly performs high-precision electric energy calculation and transfers information, data and commands with the single-chip processing system. In addition to receiving commands from the upper computer connected with the RS485/232 communication module, the single-chip processing system also processes peripheral events. The 220V AC power supply module is converted to provide working power for the DSP control system and the single-chip processing system. Three-phase voltage analog quantities Ua, Ub, Uc and three-phase current analog quantities Ia, Ib, Ic are stored in dual-port RAM after being sampled by the data acquisition circuit. The photoelectric pulse module receives the pulse from the digital electric energy meter, which is processed by the signal processing circuit and stored in the dual-port RAM. The DSP control system issues read and write commands to take out the data in the dual-port RAM for power energy and error calculation. The upper computer connected with the single-chip microcomputer mainly completes the display of error detection, which is convenient for the test personnel to view and record.

The main control chip of the DSP control system adopts TMS320F2812 of Dezhou Company.

The main control chip of the single-chip microcomputer processing system adopts 80C196 of Intel Corporation. the

Claims (6)

1. the real load error pick-up unit of an intelligent substation electric energy metering secondary, it is characterized in that, comprise the data acquisition circuit, dual port RAM, dsp processor, the single-chip microcomputer that connect successively, described dual port RAM is connected with signal processing circuit, and described signal processing circuit connects photoimpact receiver module; Described dsp processor, single-chip microcomputer are all connected with power module; Described data acquisition circuit is connected with three-phase voltage combined connection box, the three-phase current combined connection box of intelligent substation electric energy metering secondary; Described photoimpact receiver module is connected with the digital electric energy meter of intelligent substation electric energy metering secondary.

2. the real load error pick-up unit of intelligent substation electric energy metering secondary according to claim 1, is characterized in that, described dsp processor is connected with external memory.

3. the real load error pick-up unit of intelligent substation electric energy metering secondary according to claim 1, is characterized in that, described single-chip microcomputer is connected with keyboard, liquid crystal display, printer, USB interface, network interface.

4. the real load error pick-up unit of intelligent substation electric energy metering secondary according to claim 1, is characterized in that, described single-chip microcomputer is connected with host computer by communication interface.

5. the real load error pick-up unit of intelligent substation electric energy metering secondary according to claim 1, is characterized in that, described dsp processor model is TMS320F2812.

6. the real load error pick-up unit of intelligent substation electric energy metering secondary according to claim 1, is characterized in that, described single-chip microcomputer model is 80C196.

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