CN201926727U - Power quality monitor - Google Patents

Abstract

The power quality monitor provided by the utility model includes a power supply unit, an analog signal conditioning unit, a synchronous sampling A/D conversion unit, a processor unit, a network communication unit and a control output unit, wherein the analog signal conditioning unit, the synchronous sampling A/D The D conversion unit, the processor unit and the network communication unit are connected in turn, and the processor unit is also connected to the control output unit. The analog signal conditioning unit collects the voltage signal of the AC voltage transformer and the current signal of the current transformer, and synchronously samples A/ The D conversion unit feeds to the processor unit. The processor unit uses a 32-bit embedded processor chip, and sends the processed information to the network communication unit and the control output unit respectively. Its advantages and positive effects are: the capacity of the processor unit is large, it controls the timing of A/D sampling and the data access of each sampling point, fully guarantees the real-time and accuracy of the data, and provides the market with a strong data Power quality monitors with analytical capabilities.

Description

Power Quality Monitor

technical field

The utility model relates to a meter, in particular to a power quality monitor.

Background technique

With the wide application and development of power electronics technology, a large number of non-linear loads have been added to the power supply system, such as static transformers, which are used from low-voltage small-capacity household appliances to high-voltage large-capacity industrial AC-DC conversion devices. The inverter works in a switch mode, which will cause distortion of the voltage and current waveforms of the grid, and cause harmonic pollution of the grid. Impulsive and fluctuating loads such as: electric arc furnaces, large rolling mills, electric locomotives, etc. will not only generate a large number of high Subharmonics, and make voltage fluctuations, flicker, and three-phase unbalance become more and more serious. These adverse effects on the power grid will not only reduce the safety of the power supply and consumption equipment itself, but also seriously weaken and interfere with the economic operation of the power grid. On the other hand, banks, precision electronic device manufacturing, electric locomotives, computer networks and service monitoring systems are places with high requirements for power quality, and high-precision technology and equipment demand for high-quality power. Increase.

The real-time dynamic monitoring of the power quality of the power grid is the premise and foundation of the comprehensive management of power quality. At present, the real-time performance of power quality monitoring is not strong, and the monitoring methods are outdated, resulting in poor timeliness of data. The superior departments cannot timely understand the power quality level of each region and voltage level, and lack the basis for decision-making and judgment, so they cannot take corresponding measures in time to improve power quality.

Determining the cause of low power quality requires a lot of work and requires a lot of manpower and material resources to collect data. On the other hand, statistical analysis of the collected data is also required. The efficiency is low, and it often takes a long time from the discovery of the power quality problem to the solution of the problem. Insufficient data sharing ability and lack of experience exchange among personnel seriously restrict the improvement of personnel quality and hinder the progress of power quality monitoring.

At present, it is a new topic to improve the monitoring means, improve the real-time performance of power quality monitoring instruments, and develop power quality monitors with strong data analysis capabilities to meet the urgent needs of improving power quality.

Utility model content

The purpose of the utility model is to overcome the above defects and provide a power quality monitor that can improve the real-time performance of power quality monitoring and has strong data analysis capabilities.

In order to achieve the above purpose, the power quality monitor provided by the utility model includes a power supply unit, an analog signal conditioning unit, a synchronous sampling A/D conversion unit, a processor unit, a network communication unit and a control output unit, wherein the An analog signal conditioning unit, a synchronous sampling A/D conversion unit, and a processor unit are sequentially connected to the network communication unit, and the processor unit is also connected to the control output unit, and the analog signal conditioning unit collects AC voltage transformers The voltage signal of the current transformer and the current signal of the current transformer are sent to the processor unit through the synchronous sampling A/D conversion unit; the processor unit adopts a 32-bit embedded processor chip, and the processed information and sent to the network communication unit and the control output unit respectively.

In the electric energy quality monitor of the utility model, a programmable logic controller is connected between the synchronous sampling A/D conversion unit and the processor unit.

In the electric energy quality monitor of the utility model, the output of the control output unit is a relay controllable contact.

The utility model electric energy quality monitor, wherein said network communication unit is respectively provided with RJ45 network interface and RS-232/RS-485 communication interface, said processor unit is connected with RS-232/RS-485 communication interface through optocoupler unit The output of the network communication unit includes current and voltage effective value, power factor, positive sequence, negative sequence and zero sequence components of current and voltage, unbalance degree of current and voltage, active power, reactive power and apparent power, Active and reactive energy, harmonic content of current and voltage.

In the electric energy quality monitor of the utility model, the processor unit is provided with a program memory and a data memory.

The advantages and positive effects of the utility model power quality monitor are: because the processor unit adopts a 32-bit embedded processor chip and an ultra-large-scale programmable logic controller, it has the characteristics of large capacity and powerful logic programming function. In the time sequence of D sampling and the data access to each sampling point, a digital filter algorithm is used to ensure the real-time and accuracy of the data. A power quality monitor with strong data analysis capability is provided for the market.

The following will describe in detail with reference to the accompanying drawings in conjunction with the embodiments.

Description of drawings

Fig. 1 is a structural schematic diagram of the utility model power quality monitor.

Detailed ways

Referring to Fig. 1, the power quality monitor of the present invention includes a power supply unit, an analog signal conditioning unit, a synchronous sampling A/D conversion unit, a processor unit, a network communication unit and a control output unit. Among them, the analog signal conditioning unit, the synchronous sampling A/D conversion unit, the processor unit and the network communication unit are connected in sequence, and the processor unit is also connected with the control output unit. A programmable logic controller is connected between the synchronous sampling A/D conversion unit and the processor unit.

The analog signal conditioning unit collects the voltage signal of the AC voltage transformer and the current signal of the current transformer, and sends them to the processor unit through the synchronous sampling A/D conversion unit. The analog signal conditioning unit handles up to 6 standard analog inputs, sampling 128 times per cycle (can be upgraded to 256 points), and the analog input can be configured.

The processor unit uses a 32-bit embedded processor chip, and sends the processed information to the network communication unit and the control output unit respectively. The embedded real-time operating system is embedded in the processor unit, and the program can be directly downloaded through the super terminal, which is convenient for upgrade and maintenance, good portability, and reliable system, which ensures the stability of the entire terminal. The ultra-large-scale programmable logic controller is selected, which has the characteristics of large capacity and powerful logic programming functions. In controlling the timing of A/D sampling and data access to each sampling point, digital filtering algorithms are used to ensure real-time data. and precision.

The processor unit is equipped with an on-board temperature acquisition device, which can monitor the temperature of the module with an accuracy of 0.5 degrees and a measurement range of -40°C to +85°C.

The processor unit is equipped with a large-capacity program memory and data memory, RJ45 network interface and RS-232/RS-485 communication interface, and the processor unit is connected with the RS-232/RS-485 communication interface through an optocoupler unit. The output of the network communication unit includes the effective value of current and voltage (accuracy is 0.2%), power factor, positive sequence, negative sequence and zero sequence components of current and voltage, unbalance degree of current and voltage, active power, reactive power and apparent power. Power (accuracy is 0.5%), active power, reactive power, current and voltage harmonic content (2-50 times) output, measurement result refresh rate is 20ms. The output of the control output unit is a relay controllable contact.

The power quality monitor of the utility model is used to help users locate, predict, prevent and diagnose faults in the power system, and can monitor the negative sequence and harmonics of the power grid in real time, total harmonic distortion rate, voltage and current unbalance, flicker, Voltage deviation, voltage change frequency, frequency deviation, frequency change frequency, active power, reactive power, reactive power and other power quality indicators. The system calculates the harmonic power so that the impact of negative sequence and harmonics on energy metering can be analyzed.

After realizing the all-weather networked monitoring of the five indicators of power quality (voltage frequency harmonics, three-phase unbalance, voltage fluctuation and flicker), the requirements for system analysis and effective control can be realized, and the automatic management of power systems can be comprehensively improved level, strengthen the supervision and management of the power quality of the public power grid, and ensure the safe operation of the power grid. The system monitoring data can timely and accurately locate potential fault sources and pollution sources of the system, analyze the characteristics, types and distribution rules of the sources, give rectification plans to prevent power accidents, and verify whether the power network structure is reasonable and equipment parameters from the perspective of power quality Whether the equipment is reasonable, analyze the causes of power accidents from the perspective of power quality, and ultimately improve the safety and reliability of power grid operation.

The utility model electric energy quality monitor is a high-performance, economical electric energy quality analysis and monitoring terminal, which can monitor the electric energy quality in the electric power system both in a centralized manner and in a decentralized manner. The power quality of low voltage (voltage within 1KV according to EN50160 specification) and medium voltage (voltage within 35KV according to EN50160 specification) is especially important, because modern industry and home appliance industry use a large number of electronic devices, which will have a serious impact on power quality , resulting in a decrease in power quality.

The power quality monitor of the utility model can be used in a relatively closed environment such as a building, a substation, a production line, etc. to monitor the power quality. The power quality monitor can be connected to the display unit, personal computer or communication control device to record and calculate the required measurement values, such as the effective value of current and voltage, total harmonic distortion, the magnitude of each harmonic, flicker and electric energy, and Can be transmitted to the master station on request.

The above-mentioned embodiment is only to describe the preferred implementation of the utility model, not to limit the concept and scope of the utility model. The various modifications and improvements made in the technical solution should fall within the scope of protection of the utility model, and the technical content claimed in the utility model has been fully recorded in the claims.

Claims (5)

1. A power quality monitor, comprising a power supply unit, characterized in that: it also includes an analog signal conditioning unit, a synchronous sampling A/D conversion unit, a processor unit, a network communication unit and a control output unit, wherein the analog signal The conditioning unit, the synchronous sampling A/D conversion unit, and the processor unit are sequentially connected to the network communication unit, the processor unit is also connected to the control output unit, and the analog signal conditioning unit collects the voltage of the AC voltage transformer signal and the current signal of the current transformer, and are sent to the processor unit through the synchronous sampling A/D conversion unit; the processor unit adopts a 32-bit embedded processor chip, and transmits the processed information respectively to the network communication unit and control output unit. 2. The power quality monitor according to claim 1, wherein a programmable logic controller is connected between the synchronous sampling A/D conversion unit and the processor unit. 3. The power quality monitor according to claim 1 or 2, wherein the output of the control output unit is a relay controllable contact. 4. The power quality monitor according to claim 3, wherein the network communication unit is respectively provided with an RJ45 network interface and an RS-232/RS-485 communication interface, and the processor unit passes through the optocoupler unit Connected with RS-232/RS-485 communication interface, the output of the network communication unit includes current and voltage effective value, power factor, positive sequence, negative sequence and zero sequence components of current and voltage, unbalance of current and voltage , Active power, reactive power, apparent power, active power, reactive power, harmonic content of current and voltage. 5. The power quality monitor according to claim 4, wherein said processor unit is provided with a program memory and a data memory.

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