CN206557369U - On-line Monitoring System of High Voltage Electric Energy Metering Device Based on Carrier Communication - Google Patents

Abstract

The utility model discloses an on-line monitoring system of a high-voltage electric energy metering device based on carrier communication, which can measure the error of the electric energy meter on-line in real time, the error caused by the secondary pressure drop of PT, and the on-line measurement of the real load of PT and CT, etc. The integration of these functions expands the application occasions of the metering device monitoring system. Since the original secondary test circuit cable of the substation is used to transmit the sampling data, there is no need to lay a large number of secondary cables and secondary wiring, which ensures that the metering device and the secondary normal operation of the circuit.

Description

On-line Monitoring System of High Voltage Electric Energy Metering Device Based on Carrier Communication

technical field

The utility model relates to the technical field of power systems, in particular to an on-line monitoring system for high-voltage electric energy metering devices based on carrier communication.

Background technique

The research and development of on-site inspection instruments for electric energy metering devices in the world began in the mid-1980s. In the early 1990s, domestic manufacturers successively launched the first generation of on-site inspection instruments using analog technology. In the mid-1990s, a single-function second-generation on-site tester using digital technology appeared. After 2000, the third-generation single-function on-site inspection instrument with the characteristics of high precision, small size, light weight and convenience and ease of use has appeared at home and abroad. At present, our country has widely promoted the third-generation on-site inspection instrument.

The electric energy meter on-site tester and the PT secondary voltage drop tester only have the single functions of electric energy meter error measurement and PT secondary voltage drop test respectively. The current on-site inspection all-in-one machine needs to arrange a large number of cables to connect to the secondary circuit of voltage and current, which has great risks and hidden dangers for the normal operation of on-site metering devices and circuits. The inspection instrument that does not need to arrange a large number of cables adopts a wireless network method, and the communication is unstable. , and therefore failed to promote.

Utility model content

Aiming at the deficiencies of the prior art, the purpose of this utility model is to provide an on-line monitoring system for high-voltage electric energy metering devices based on carrier communication, which integrates various measurement functions and ensures the stability of measurement data transmission.

In order to achieve the above object, the technical scheme that the utility model takes is:

An on-line monitoring system for high-voltage electric energy metering devices based on carrier communication, including a measurement host, PT measurement extensions, CT measurement extensions, and front-end processors;

The front-end processor is located in the main control room of the substation, the measurement host is located in the measurement screen cabinet of the main control room of the substation, and the PT measurement extension and CT measurement extension are respectively located in the PT secondary terminal box and CT secondary terminal box in the primary equipment area of the substation;

The PT measurement extension is connected to the PT, the CT measurement extension is connected to the CT, the PT measurement extension and the CT measurement extension are respectively connected to the measurement host through the secondary test circuit cable, and the measurement host is also connected to the front-end processor and the electric energy meter.

The utility model integrates multiple functions such as real-time on-line measurement of the error of the electric energy meter, real-time on-line measurement of the error caused by the secondary voltage drop of the PT, and on-line measurement of the actual load of the PT and CT, and expands the application occasions of the metering device monitoring system. Since the original secondary test circuit cable of the substation is used to transmit the sampling data, there is no need to lay a large number of secondary cables and secondary wiring, which ensures the normal operation of the metering device and the secondary circuit.

Description of drawings

Fig. 1 is the structure schematic diagram of the on-line monitoring system of the high-voltage electric energy metering device based on the carrier communication of the present invention;

Fig. 2 is a schematic circuit diagram of the measuring host in the on-line monitoring system of the high-voltage electric energy metering device based on the carrier communication of the present invention.

detailed description

A high-voltage electric energy metering device usually consists of a potential transformer (PT), a current transformer (CT) and an electric energy meter. Correspondingly, the error of the high-voltage electric energy metering device is composed of several parts such as PT error, CT error, error caused by the secondary voltage drop of PT and the error of the electric energy meter. The utility model integrates multiple functions such as real-time on-line measurement of electric energy meter error and real-time on-line measurement of error caused by PT secondary voltage drop, and develops an innovative on-line monitoring system for high-voltage electric energy metering devices based on carrier technology. The following is the monitoring The structure of the system is described in detail.

The on-line monitoring system of the high-voltage electric energy metering device based on the carrier communication of the present invention, as shown in FIG. 1 , includes a measuring host, a PT measuring extension, a CT measuring extension and a front-end processor.

The measurement host is located in the special measurement panel cabinet in the main control room of the substation, and completes the measurement of voltage, current, power, power factor, frequency, phase and electric energy, and simultaneously completes the error caused by the PT secondary voltage drop together with the PT measurement extension Measurement.

The front-end processor can be placed in the main control room of the substation to complete the local display and storage of measurement data, and provide communication protocol interfaces such as IEC103 and IEC61850.

The PT measurement extension is located in the PT secondary terminal box, connects to the PT, completes the PT secondary load measurement, and completes the measurement functions such as the error caused by the PT secondary voltage drop together with the measurement host, and is equipped with a separate circuit breaker when incorporated into the PT terminal , When the online monitoring system is abnormal, it will not affect the normal operation of the PT circuit.

The CT measurement extension is located in the CT secondary terminal box, connected to the CT, and completes the CT secondary load measurement function. The CT measurement extension obtains the CT current through induction, and is not connected in series with the existing CT circuit to ensure the normal operation of the existing CT circuit, and Sampling of existing CT loops is not affected.

The schematic diagram of the measurement host circuit is shown in Figure 2. The measured three-phase AC voltage Ua, Ub, Uc and three-phase AC current Ia, Ib, Ic on the instrument side are sequentially connected to the signal conditioning and multi-channel selection module, and the MCU judges through the high-speed serial port 1 or the dedicated keyboard processor LPC932 The control command input by the computer or the keyboard command input through the keyboard, and according to the control command or keyboard command control signal conditioning and multi-channel selection module, select two input signals with appropriate range and one sampling reference signal, and send them to 16-bit respectively Analog-to-digital converters A/D1 and A/D2 and the input of the all-digital frequency multiplier. The output signal of the all-digital frequency multiplier controls the two analog-to-digital converters to perform analog-to-digital conversion at the same time, and the conversion results A/D1 and A/D2 are sent to the 32-bit MCU for calculation and processing to complete the voltage, current, power and electric energy. Isometric measurement. At the same time, the MCU sends the secondary voltage drop measurement command to the PT measurement extension through the high-speed serial port 2, and makes the output signal of the all-digital frequency multiplier control the analog-to-digital conversion of the PT measurement extension through the original secondary test loop cable as a carrier At the same time, the voltage amplitude, voltage phase and electric energy value of the PT terminal on the secondary side of the voltage transformer are measured. The resulting energy measurement error. In addition, the six channels of tested signals that have been shaped are directly input to the MCU, and the frequency and phase difference are measured by the MCU. Then, the MCU sends the measured measurement results to the front-end processor through the high-speed serial port 1 or directly to the dot-matrix liquid crystal display for display.

In the design of the hardware circuit, the conditioning circuit of the voltage signal adopts a high-precision resistor divider network; the conditioning of the current signal adopts the comprehensive compensation technology of software and hardware; the power supply part adopts the switching power supply technology. Thereby greatly reducing the volume and weight of the instrument.

The front-end machine is a dedicated EPIC standard industrial computer. The design adopts 8.4" industrial-grade wide-temperature TFT LCD screen, stainless steel metal panel and keyboard, solid-state electronic hard disk, on-board SDRAM and relay protection power supply, etc., with high reliability. At the same time, the front-end machine has eight High-speed serial interface, two 100M Ethernet ports and two RS485 ports can control up to eight measurement hosts and meet various networking needs.

The voltage measurement, current sampling design and data transmission mode of the extension are the same as those of the host, and will not be repeated here. It should be noted that the PT measurement extension and the CT measurement extension respectively use the original secondary test circuit cable of the substation as the carrier to transmit the measurement data to the measurement host, which is the so-called carrier communication, without laying a large number of secondary cables and secondary Wiring ensures the normal operation of the metering device and the secondary circuit.

As a preferred embodiment, the measurement host includes an MCU, a high-speed serial port 1, a high-speed serial port 2, a high-speed serial port 3, a standard source 1 and a standard source 2. As shown in Figure 2, one end of the high-speed serial port 1 is connected to the front-end computer, and the other end is connected to the MCU. One end of the high-speed serial port 2 is connected to the PT measurement extension, and the other end is connected to the MCU. Connect standard source 1 and standard source 2 respectively.

The two standard sources compare the measured data to realize the online error verification of the electric energy meter. Configuration of standard source: standard table level: 0.02 level. It can check and compare the on-site gateway and non-gate tables. Dual-standard source configuration can be compared with each other for reference, without on-site calibration, and an alarm will be issued if the error is too large. The measurement host records the measurement data before and after the alarm, and saves the data for power replenishment for fault handling.

The above detailed description is a specific description of the feasible embodiment of the utility model. This embodiment is not used to limit the patent scope of the utility model. Any equivalent implementation or change that does not deviate from the utility model shall be included in this case within the scope of the patent.

Claims (3)

1. A high-voltage electric energy metering device online monitoring system based on carrier communication, characterized in that, Including measurement host, PT measurement extension, CT measurement extension and front-end processor; The front-end processor is located in the main control room of the substation, the measurement host is located in the measurement screen cabinet of the main control room of the substation, and the PT measurement extension and CT measurement extension are respectively located in the PT secondary terminal box and CT secondary terminal box in the primary equipment area of the substation; The PT measurement extension is connected to the PT, the CT measurement extension is connected to the CT, the PT measurement extension and the CT measurement extension are respectively connected to the measurement host through the secondary test circuit cable, and the measurement host is also connected to the front-end processor and the electric energy meter. 2. The high-voltage electric energy metering device online monitoring system based on carrier communication according to claim 1, characterized in that, The measurement host includes MCU, high-speed serial port 1, high-speed serial port 2, high-speed serial port 3, standard source 1 and standard source 2; One end of the high-speed serial port 1 is connected to the front-end computer, and the other end is connected to the MCU. One end of the high-speed serial port 2 is connected to the PT measurement extension, and the other end is connected to the MCU. One end of the high-speed serial port 3 is connected to the CT measurement extension, and the other end is connected to the MCU. Standard source 2. 3. The high-voltage electric energy metering device online monitoring system based on carrier communication according to claim 2, characterized in that, The front-end computer is an EPIC standard industrial computer, including an 8.4" industrial-grade wide-temperature TFT LCD screen, a stainless steel metal panel and keyboard, a solid-state electronic hard disk, on-board SDRAM and a relay power supply. At the same time, it also includes eight high-speed serial interfaces, two One 100M Ethernet port and two RS485 ports.