CN202066925U

CN202066925U - Harmonic monitor of electric network

Info

Publication number: CN202066925U
Application number: CN2011201334622U
Authority: CN
Inventors: 张源
Original assignee: Chuzhou Li Hua Electric Co ltd
Current assignee: Chuzhou Li Hua Electric Co ltd
Priority date: 2011-04-29
Filing date: 2011-04-29
Publication date: 2011-12-07
Anticipated expiration: 2021-04-29

Abstract

The utility model discloses a harmonic monitor of an electric network, comprising a singlechip; a single input end of the singlechip is respectively connected with a voltage sampling holding circuit, a voltage period test circuit, a current sampling holding circuit and a current period test circuit, and a signal output end of the singlechip is respectively communicated with a host computer and a warning circuit. Through the harmonic monitor of the electric network, all-weather monitoring can be performed on electric quantities of a converting station bus or a low voltage electric network such as frequency, harmonic waves, voltage, current, power factors, positive-negative sequence voltage, positive-negative sequence current, unbalance degree, reactive power, active power, active electric degree, reactive electric degree and the like, so as to provide the basis for comprehensively grasping electric network quality, electric network reconstruction, electric network harmonic suppression; and the harmonic monitor has high measurement precision and good reliability.

Description

The mains by harmonics monitor

Technical field

The utility model belongs to monitor, belongs to a kind of mains by harmonics monitor especially.

Technical background

In recent years, along with the development of metallurgical industry, chemical industry and electric railway, and direct current transportation, the widespread use of high-power single-phase rectifier technology on industrial sector and consumer, the pollution of electric system is also serious day by day.The impact power load can make line voltage fluctuate after dropping into operation of power networks, thereby has seriously disturbed the normal operation of fluctuate in the electrical network sensitive load such as illumination, computing machine, precision electronic device etc.In case power quality problem occurs, gently then cause equipment failure, heavy then cause the damage of total system, the loss that brings thus is difficult to the appraisal.In addition, a large amount of for enhancing productivity, what energy savings adopted with reducing environmental pollution is just becoming the main source of power quality problem based on the state-of-the-art facility of Power Electronic Technique.

The utility model content

Technical problem to be solved in the utility model provide a kind of can the on-line real time monitoring quality of power supply, the mains by harmonics monitor of measuring accuracy height, good reliability.

The technical scheme of the utility model technical solution problem is: a kind of mains by harmonics monitor, comprise single-chip microcomputer, its signal input part keeps loop, voltage cycle test loop, current sample to keep loop, current cycle test loop to link to each other with voltage sample respectively, its signal output part respectively with host computer and warning circuit communication.

The utility model compared with prior art, the utility model is sampled to three-phase alternating voltage by voltage sample maintenance loop and voltage cycle test loop and is tested, keep loop and current cycle test loop three-phase alternating current is sampled and to test by current sample, and above-mentioned sampling test data is sent to single-chip microcomputer, output control signals to host computer and warning device after by single-chip microcomputer data being handled.The utility model carries out round-the-clock monitoring to electric weight such as the frequency of substation bus bar or low voltage electric network, harmonic wave, voltage, electric current, power factor (PF), positive-negative sequence voltage, positive-negative sequence current, degree of unbalancedness, idle, meritorious, active electrical degree, idle electric degrees, provide foundation, measuring accuracy height, good reliability for grasp power grid quality, electric network reconstruction and power network harmonic wave management comprehensively.

Description of drawings

Fig. 1 is a circuit block diagram of the present utility model.

Embodiment

A kind of mains by harmonics monitor, comprise single-chip microcomputer 5, its signal input part keeps loop 1, voltage cycle test loop 2, current sample to keep loop 3, current cycle test loop 4 to link to each other with voltage sample respectively, its signal output part respectively with host computer and warning circuit communication, as shown in Figure 1.The quality of voltage data comprise: operation T.T., qualified time, qualification rate; Super upper limit time, super upper limit rate, super lower limit time, super lower limit rate; The time of maximum voltage value, minimum voltage value and appearance thereof.The harmonic monitoring data comprise: total harmonic voltage content and aberration rate, 3-31 subharmonic voltage component and containing ratio; Total harmonic current content and aberration rate, 3-31 subharmonic current component and containing ratio; Harmonic voltage distorts when qualified and time of qualification rate, distortion maximal value and appearance thereof; Harmonic current distorts when qualified and time of qualification rate, distortion maximal value and appearance thereof.

As shown in Figure 1, described single-chip microcomputer 5 adopts the LPC2214 chip, the signal input part of LPC2214 chip keeps loop 1 with voltage sample respectively, voltage cycle test loop 2, current sample keeps the output terminal of loop 3 and current cycle test loop 4 to link to each other, voltage sample keeps loop 1, the input end of voltage cycle test loop 2 all links to each other with the output terminal of voltage conversion circuit, the input termination three-phase alternating voltage of voltage conversion circuit, current sample keeps the input end of loop 3 and current cycle test loop 4 all to link to each other the input termination three-phase alternating current of current conversion circuit with the output terminal of current conversion circuit.

Voltage conversion circuit and current conversion circuit are used for the three-phase alternating current of input is carried out step-down, current limliting, and export voltage sample to and keep loop 1, voltage cycle test loop 2, current sample to keep loop 3 and current cycle test loop 4, voltage sample keeps loop 1, voltage cycle test loop 2, current sample to keep voltage, electric current after loop 3 and 4 pairs of conversion of current cycle test loop to sample, test, and export sampling, test signal to the LPC2214 chip, the LPC2214 chip is handled sampling, test signal.

As shown in Figure 1, the signal output part of described LPC2214 chip links to each other with display screen 6, keyboard and storer respectively, serial ports 7 is set on the LPC2214 chip, and the signal output part of LPC2214 chip is by serial ports 7 and upper machine communication, and described serial ports 7 is RS232 serial ports or RS485 serial ports.The signal output part of described LPC2214 chip links to each other with the input end of photoelectric isolating driving circuit 8, and the output terminal of photoelectric isolating driving circuit 8 links to each other with warning circuit.Available host computer collection in worksite, or carry out data transmission by carrier wave, negative control etc.; Host computer is based on the WINDOWS operating platform, and the data of various collections can both generate various forms, curve, rod figure automatically.

Instrument monitoring also shows below electrical energy parameter in real time: three-phase voltage, electric current and mains frequency, power factor; Three-phase 3-31 subharmonic voltage, harmonic current containing ratio; Three-phase voltage, current harmonics resultant distortion rate; Three-phase voltage, current imbalance degree; Positive sequence voltage, negative sequence voltage, forward-order current, negative-sequence current and zero-sequence current; Three phases active power, reactive power, active electrical degree, idle electric degree; Working time.

Claims

1. A power grid harmonic monitor, characterized in that: comprising a single-chip microcomputer (5), its signal input terminal is respectively connected to a voltage sampling and holding circuit (1), a voltage cycle testing circuit (2), a current sampling and holding circuit (3), The current cycle test circuit (4) is connected, and its signal output terminal communicates with the upper computer and the alarm circuit respectively.

2. The grid harmonic monitor according to claim 1, characterized in that: the single-chip microcomputer (5) adopts the LPC2214 chip, and the signal input terminal of the LPC2214 chip is respectively connected with the voltage sampling and holding circuit (1) and the voltage cycle test circuit (2), the current sampling and holding circuit (3) is connected to the output terminal of the current cycle test circuit (4), and the input terminals of the voltage sampling and holding circuit (1) and the voltage cycle test circuit (2) are connected to the output terminal of the voltage conversion circuit The input terminal of the voltage conversion circuit is connected to the three-phase AC voltage, the input terminals of the current sampling and holding circuit (3) and the current cycle test circuit (4) are connected to the output terminal of the current conversion circuit, and the input terminal of the current conversion circuit is connected to three phase alternating current.

3. The power grid harmonic monitor according to claim 2, characterized in that: the signal output terminals of the LPC2214 chip are respectively connected to the display screen (6), keyboard and memory, and a serial port (7) is set on the LPC2214 chip, The signal output terminal of the LPC2214 chip communicates with the host computer through the serial port (7).

4. The power grid harmonic monitor according to claim 2, characterized in that: the signal output terminal of the LPC2214 chip is connected to the input terminal of the photoelectric isolation drive circuit (8), and the output of the photoelectric isolation drive circuit (8) connected to the alarm circuit.

5. The grid harmonic monitor according to claim 3, characterized in that: the serial port (7) is an RS232 serial port or an RS485 serial port.