CN203433105U - Virtual load error detector for secondary electric-energy metering system of intelligent transformer station - Google Patents

Abstract

The utility model discloses a virtual load error detector for a secondary electric-energy metering system of an intelligent transformer station. The detector comprises an in-situ electric energy meter verifying instrument and a high-precision analog signal source, a three-phase voltage output by the high-precision analog signal source and an analog current are simultaneously input into the detected secondary electric-energy metering system of the intelligent transformer station and the in-situ electric energy meter verifying instrument, an electric energy pulse of a digital electric energy meter in the secondary electric-energy metering system is also input into the in-situ electric energy meter verifying instrument, and the electric energy of the secondary electric-energy metering system is compared with that of the in-situ electric energy meter verifying instrument, thereby comprehensively detecting the virtual load of the secondary electric-energy metering system of the intelligent transformer station. According to the utility model, the difficulty in comprehensively detecting the virtual load of the secondary electric-energy metering system of the intelligent transformer station is overcome, and the detector is easy to use, and highly economical, reliable and safe.

Description

Virtual load error detection device for secondary system of electric energy metering in smart substation

technical field

The utility model relates to the technical field of electric energy metering device calibration during debugging of an intelligent substation in an intelligent grid, in particular to a virtual load error detection device for a secondary system of electric energy metering in an intelligent substation. the

Background technique

The contradiction between the depletion of traditional energy sources and the increasing demand for electricity due to the rapid development of human beings is becoming more and more prominent. In order to solve the problem of electricity crisis, smart grid has become a key research object of governments, power departments and scientific research institutions. The concept of smart grid in the world has been formed in a process. Due to the different development levels and states of power grids in various countries, the goals, starting points, driving factors, and development ideas of countries to build a power grid that meets future development needs are different. The United States proposes to use cost-effective computers, electronic equipment and controllable power components as the basis, and use network communication technology, automatic control and information technology to combine these technologies with the original power transmission and distribution infrastructure. power grid. Europe proposes to link electricity with communications and computer control to reap huge benefits in power supply reliability, transmission capacity, and customer service. The State Grid Corporation of my country has formed a strategic development framework for a strong smart grid with Chinese characteristics of "one goal, two main lines, three stages, four systems, and five connotations".

The development of smart grid is inseparable from the construction of smart substations. The research and development of smart substation related technologies has attracted the attention of many power users, scientific research, design and manufacturing departments. The development of my country's smart grid has been at the forefront of the world, and many smart substations have been established. At this time, the electric energy metering mode of the substation has undergone a qualitative change, and the composition and working mode of the electric energy metering secondary system have also undergone qualitative changes: the electric energy metering system in the traditional substation consists of electromagnetic current/voltage transformers (output analog Signal), electric energy meter and connecting cable. The secondary system of electric energy metering in traditional substation is mainly composed of secondary cable of traditional current/voltage transformer and electric energy meter with analog signal interface; in smart substation, the secondary system of electric energy metering is mainly composed of Consists of merging unit with analog-to-digital converter, optical fiber and digital energy meter.

The structure and composition of the secondary system of electric energy metering in smart substations are very different from traditional substations. At the same time, the accuracy of the entire secondary system of electric energy metering has a great influence on the amount of electricity; moreover, the secondary system of electric energy metering in traditional substations can pass Measure the secondary voltage drop of the voltage transformer and the secondary load of the entire secondary circuit to determine whether its accuracy level meets the regulations, so as to ensure the fairness and justice of electric energy measurement. However, the structure and working mechanism of the secondary system of electric energy metering in smart substations are different from those of traditional substations. The error detection method of the secondary system of electric energy metering in traditional substations is no longer suitable for error detection in the secondary system of electric energy metering in smart substations, especially for electric energy metering in smart substations. The secondary system introduces a merging unit with an analog-to-digital converter. After the voltage and current analog signals are converted into digital signals, they are provided for electric energy metering. During the conversion process, the accuracy of the electric energy metering signal is inevitably affected. At present, by consulting domestic and foreign literature, there is no report on the overall error detection of the secondary system of electric energy metering in smart substations. the

Contents of the invention

The technical problem to be solved by the utility model is to provide a virtual load error detection device for the secondary system of electric energy metering in intelligent substations to meet the requirements of virtual load error detection for the secondary system of electric energy metering in intelligent substations.

In order to solve the above technical problems, the technical solution adopted by the utility model is: a virtual load error detection device for the secondary system of electric energy metering in intelligent substations, including an electric energy meter field calibrator and a high-precision analog signal source, and the electric energy meter field The calibrator is connected in parallel between the current transformer of the secondary system of electric energy metering in the smart substation and the current merging unit under test; Between the voltage transformer of the sub-system and the voltage merging unit under test, the field calibrator of the electric energy meter is connected with the digital electric energy meter of the secondary system of the electric energy metering of the intelligent substation; the output terminal of the field calibrator of the electric energy meter is connected with the upper computer connection; the output end of the high-precision analog signal source is connected to the field calibrator of the electric energy meter.

，并通过光电转换器把电能脉冲传输到电能表现场校验仪；高精度模拟信号源输出的三相电压模拟量和三相电流模拟量接入电能表现场校验仪进行电能计算，得出虚拟负荷的电能值，即标准电能值

；电能表现场校验仪对

和

进行比较，计算出电能计量二次系统虚负荷下计量误差，完成对智能变电站电能计量二次系统虚负荷下的整体检测。 The method of the utility model for detecting the virtual load error of the secondary system of electric energy metering of the intelligent substation is as follows: the three-phase voltage analog quantity output by the high-precision analog signal source is transmitted to the voltage merging unit to be converted into a voltage digital signal in FT3 format, and the voltage digital signal in FT3 format The signal is transmitted to the current merging unit through optical fiber, and the three-phase current analog output from the high-precision analog signal source is converted into a current digital signal by the current merging unit, and the voltage digital signal and current digital signal in FT3 format are packaged by the current merging unit into IEC61850- 9-2 The digital signal in the message format is transmitted to the digital electric energy meter through the network switch of the secondary system of electric energy metering in the smart substation, and the digital electric energy meter calculates the electric energy under the condition of virtual load

, and transmit the electric energy pulse to the electric energy meter field calibrator through the photoelectric converter; the three-phase voltage analog quantity and the three-phase current analog quantity output by the high-precision analog signal source are connected to the electric energy meter field calibrator for electric energy calculation, and the The electric energy value of the virtual load, that is, the standard electric energy value

; Electric energy meter on-site calibrator pair

and

By comparison, the measurement error under the virtual load of the secondary system of electric energy metering is calculated, and the overall detection of the secondary system of electric energy metering of the smart substation under the virtual load is completed.

计算公式为： The Error of Secondary System of Electric Energy Metering under Virtual Load

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, C is the constant of the digital energy meter

Compared with the prior art, the utility model has the beneficial effects as follows: the device of the utility model is simple in structure and reliable in operation; using the device of the utility model, the calibration personnel can operate without any electrical contact with the primary high-voltage circuit Virtual load error detection; solves the problem that the secondary system of electric energy metering in intelligent substations cannot perform overall detection and verification, and the device of the utility model is simple and easy to operate, and has high economy, reliability, safety and high efficiency sex.

Description of drawings

Figure 1 is a schematic diagram of the connection between the virtual load detection device of the present invention and the secondary system of electric energy metering.

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的整体误差。数字式电能表的输出脉冲被传送到电能表现场校验仪，并由电能表现场校验仪把

与

进行比较，计算出电能计量二次回路虚负荷下的有功、无功计量误差，完成对智能变电站电能计量二次回路虚负荷下的整体检测。误差计算公式为： As shown in Figure 1, the high-precision analog signal source (model: DK-56C2) simultaneously outputs three-phase voltage analog quantities U _a , U _b , U _c and three-phase current analog quantities I _a , I _b , I _c . The voltage combining unit and the current combining unit under test after the secondary circuit of the traditional voltage transformer and the secondary circuit of the traditional current transformer are respectively connected, and the safety factor is considered to prevent the voltage and current transformer from secondary to primary reverse boosting and For boosting current, the secondary circuit circuit breaker of voltage transformer and current transformer must be disconnected. At the same time, U _a , U _b , U _c and I _a , I _b , I _c are also input into the field calibrator of the electric energy meter, and the electric energy value of the virtual load is calculated, that is, the standard electric energy value . Three-phase voltage analog quantities U _a , U _b , U _c are input to the tested voltage merging unit with analog-to-digital converter, converted into digital messages in FT3 format, and transmitted to the tested unit with analog-to-digital converter through optical fiber Current Merging Unit. The three-phase current analog quantities I _a , I _b , and I _c are input to the current combining unit under test with an analog-to-digital converter, and the current combining unit under test converts the voltage signal and digital current signal in FT3 format into IEC61850-9-2 format message, and transmit it to the network switch through the optical fiber, and then the network switch transmits the three-phase voltage and current signals to the digital electric energy meter through the optical fiber, and the digital electric energy meter calculates the electric energy under the condition of virtual load

. Electric energy value measured by digital electric energy meter

It can not only reflect the error of the tested voltage combining unit and 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 error of the secondary circuit of electric energy measurement. The output pulse of the digital electric energy meter is transmitted to the field calibrator of the electric energy meter, and the field calibrator of the electric energy meter

and

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

     （1）

(1)

(2)

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

(3)

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

The upper computer system software is installed in the upper computer, and the upper computer system software is composed of five functional modules, namely: real-time data module, historical data module, system and parameter setting module, active power accuracy test module, reactive power accuracy test module, each function All modules can be switched and printed freely. The parameter setting module can realize the setting of the calibration channel, pulse constant and pulse number, basic information of the secondary circuit of the measured electric energy metering and other functions during the calibration of active power and reactive power accuracy. The real-time data module can realize the display of real-time waveform and data of active power and reactive power accuracy test. Calibration personnel can also view the qualified and unqualified data saved in the previous calibration through the historical data module, which is convenient for analysis and finding reasons. The main help module in the main screen of the virtual load test has instructions on how to operate the system software and an introduction to the function characteristics of each module, which can be conveniently consulted by the experiment operator at any time. The upper computer system software can also set the login user name and security password to ensure the security of the experimental settings and experimental data. the

Claims (1)

1. A virtual load error detection device for a secondary system of electric energy metering in an intelligent substation, characterized in that it includes an electric energy meter field calibrator and a high-precision analog signal source, and the electric energy meter field calibrator is connected in parallel to the electric energy metering of the intelligent substation Between the current transformer of the secondary system and the current combining unit under test; the output terminals of the electric energy meter field calibrator and the high-precision analog signal source are all connected in parallel to the voltage transformer of the secondary system of the smart substation electric energy metering and combined with the tested voltage Between the units, the electric energy meter field calibrator is connected to the digital electric energy meter of the secondary system of electric energy metering in the smart substation; the output terminal of the electric energy meter field calibrator is connected to the host computer; the high-precision analog signal source output The terminal is connected with the field calibrator of the electric energy meter.

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