CN204044239U - A kind of measurement mechanism of the AC Electric Power analog signals based on linear optical coupling - Google Patents

Abstract

The utility model relates to the technical field of power measurement, in particular to a measuring device for measuring and detecting a DC signal on a secondary side of a power system field test based on a linear optocoupler for a power AC analog signal. The utility model is a measuring device for power AC analog signal based on linear optocoupler, which includes a lower computer, a higher computer and application software equipped with modular functional hardware. The DC isolation circuit is set with a linear optocoupler circuit. The utility model has the advantages of a measuring device for an electric AC analog signal based on a linear optocoupler: 1. The portable electricity analyzer of the utility model adopts the linear optocoupler isolation technology in its internal DC isolation technology. 2. The signal measured by the linear optocoupler isolation technology is a common signal of AC and DC. 3. The adopted linear optocoupler isolation circuit adopts the method of raising the signal on the primary side and lowering the signal on the secondary side, so that the AC signal can be measured.

Description

A measurement device for power AC analog signal based on linear optocoupler

technical field

The utility model relates to the technical field of power measurement, in particular to a measuring device for measuring and detecting a DC signal on a secondary side of a power system field test based on a linear optocoupler for a power AC analog signal.

Background technique

In order to realize various functions such as data acquisition, equipment control, measurement, parameter adjustment and various signal alarms, it is necessary to collect and isolate the signals sensed by sensors such as pressure, temperature, humidity, flow rate, speed, liquid level and displacement on site. Conversion processing. Due to differences in working methods, power distribution, output signal types and other aspects of different sensors, the function selection and matching of isolation amplifier products are also different.

DC signal isolation measurement technology is widely demanded in power systems, from 4-20mA DC current signals to secondary ratio DC voltage signals of generator excitation voltage and excitation current, and some of these signals are even as high as 2000V. Moreover, these signals do not change slowly in the experiment like traditional pressure, temperature, humidity, flow, speed, liquid level, displacement and other signals, and do not require high response speed. These signals require a corresponding speed of more than 0.1ms, which requires higher requirements for signal isolation technology. However, conventional typical linear optocoupler circuits can only input DC signals, not AC signals.

Contents of the invention

The technical problem to be solved by the utility model is to provide a measuring device for an electric AC analog signal based on a linear optocoupler for the deficiencies in the prior art.

The utility model is based on a linear optocoupler-based power AC analog signal measuring device through the following technical solutions: a linear optocoupler-based power AC analog signal measuring device includes a lower-level module with modular functional hardware Computer, upper computer and application software, the lower computer chassis adopts plug-in connection, and the DC isolation circuit of the lower computer is provided with a linear optocoupler circuit.

Compared with the prior art, a measuring device for electric AC analog signal based on a linear optocoupler of the utility model has the following beneficial effects: the measuring device of the utility model adopts a linear optocoupler circuit, can input AC and DC signals, and can realize the Measurement of on-site generator excitation voltage excitation current signals, AC voltage and current signals, 4-20mA signals and ±20V AC/DC general signals. The utility model also uses a photoelectric DC isolation circuit, and the isolation device realizes DC isolation measurement through the photoelectric isolation circuit. The utility model has the advantages of high withstand voltage, small zero drift, good precision, fast response speed, and good linearity. measurement accuracy and reliability. The utility model is a measuring device for power AC analog signal based on linear optocoupler, which makes the DC signal measurement more accurate and convenient, and saves the user from the trouble of using the traditional Hall sensor for zero calibration; and makes the whole device smaller in size, Lighter weight and easy operation.

The utility model has the following advantages of a measuring device based on a linear optocoupler for an electric AC analog signal: 1. The utility model relates to a portable power analyzer for the measurement and detection of the secondary side of the field test of the electric power system and the measurement of the laboratory, and the internal DC isolation technology adopts the linear optocoupler isolation technology.

2. The utility model adopts the linear optocoupler isolation technology, and the measured signal is a common signal of AC and DC.

3. The linear optocoupler isolation circuit adopted by the utility model adopts the method of raising the signal on the primary side and lowering the signal on the secondary side, so that the AC signal can be measured.

Description of drawings

A measuring device of the utility model based on a linear optocoupler for an electric AC analog signal has the following drawings:

Fig. 1 is a schematic diagram of the appearance structure of a measuring device for a power AC analog signal based on a linear optocoupler of the present invention;

Fig. 2 is a schematic structural diagram of a voltage raising circuit of a measuring device based on a linear optocoupler for an electric AC analog signal of the present invention;

Fig. 3 is a structural schematic diagram of an optocoupler and step-down circuit of a measuring device for power AC analog signals based on a linear optocoupler of the present invention.

Among them: 1. Lower computer; 2. Upper computer; 3. Application software; 4. DC isolation circuit; 5. Linear optocoupler circuit; 6. Signal card socket.

Detailed ways

The following will further describe the technical solution of a linear optocoupler-based power AC analog signal measuring device of the present invention in conjunction with the accompanying drawings and embodiments.

As shown in Fig. 1-Fig. 3, a measurement device based on a linear optocoupler for power AC analog signals includes a lower computer 1, an upper computer 2, and an application software 3 equipped with modular functional hardware. The lower computer 1 chassis uses Plug-in card connection, the DC isolation circuit 4 of the lower computer 1 is provided with a linear optocoupler circuit 5 .

The linear optocoupler circuit 5 is a high-precision linear optocoupler circuit of HCNR201.

The linear optocoupler circuit 5 set by the lower computer 1 is set as the following board:

a) Signal card 1 - excitation voltage, current conditioning card:

One high-voltage isolated AC and DC mixed-use high-voltage channel has 5 terminals. When in use, the measurement signal can be connected to the lower computer 1 through the signal card socket 6. The socket 6 is set to four levels of 5V, 500V, 1000V, and 2000V; Select an appropriate range according to the actual situation. The input signal of this channel mainly measures the rotor voltage of the generator and the output voltage of the regulator. One high-voltage isolated AC and DC mixed weak voltage channel with a range of ±100mV, used to measure generator rotor current and exciter excitation current.

b) Signal card 2 - general AC and DC voltage signal conditioning card:

Four ordinary AC and DC mixed channels, the measuring range is ±20V, the signal card socket 6 has four sets of signal terminals U1-U4, and the isolation voltage is 3000V.

c) Signal card 3 —— 4-20mA conditioning card:

The signal card socket 6 has a total of 8 channels of 4-20mA signal input, the linearity can reach 0.2%, and the isolation voltage is 5000V.

The host computer 2 is a portable notebook, and the application software 3 is installed on the notebook, which is convenient for the user to carry and carry out on-site operations. Its main function is to display, record, analyze, process and output data, and it is the main interface for information communication with operators. The application software receives the data from the lower computer, and processes the data so that it can intuitively and real-time display the information of various measurement signals on site through graphics, data, electronic instruments, electronic forms, etc.

Example 1.

The analyzer is mainly composed of three parts: lower computer (modular function hardware), upper computer (computer) and application software. The lower computer hardware adopts a chassis with a height of 3U and a width of 19*2/3 inches. The inside of the chassis adopts a plug-in card design, and its main function is to isolate and transform analog signals such as high voltage and high current on site, and convert them into digital signals, and send these measured quantities to the computer through high-speed serial communication; at the same time, the lower computer also passes High-speed serial communication accepts various commands from the computer to drive its own relay to control on-site alarm signals and other switching signals. The hardware of the lower computer needs to measure the field generator excitation voltage excitation current signal, AC voltage and current signal, 4-20mA signal and ±20V AC and DC general signal, etc. These signal conditioning uses the DC isolation technology mentioned this time. These signal conditioning boards can also be customized according to the needs of different users. Due to the plug-in design, users only need to replace the signal conditioning board.

This technology uses the HCNR201 high-precision linear optocoupler provided by Agilent.

The HCNR201 high linearity analog optocoupler contains a high performance AlGaAs LED and two highly matched photodiodes. The input photodiode can be used to monitor and stabilize the photometric output of the LED, so the non-linear and drift characteristics of the LED are almost eliminated, and the output photodiode will generate a photocurrent linearly corresponding to the light output of the LED. Close matching between photodiodes and advanced packaging The design ensures high linearity and stable gain of the optocoupler.

HCNR201 can be used to provide analog signal isolation for a wide range of applications that require good stability, linearity, bandwidth, and low cost. HCNR201 has high flexibility and can bring many different operating modes through proper design of the application circuit, including single polar/bipolar, AC/DC, and inverting and non-inverting, the HCNR201 is an excellent solution to many analog isolation problems. It has the following characteristics:

· 0.01% ultra-low nonlinearity

· K3 (IPD2/IPD1) conversion gain +/-5%

· -65 ppm/°C low gain temperature coefficient

· DC to > 1MHz high bandwidth

· Certified by global safety regulations:

- UL1577, 5kVrms/1min - CSA - IEC/EN/DIN EN 60747-5-2, Viorm = 1414Vpeak.

Through the circuit shown in Fig. 2 and Fig. 3 of the utility model, an AC voltage signal can be conveniently input, and a withstand voltage isolation of 5000V/1min can be realized. With this circuit and the front-end voltage dividing resistor, the generator excitation voltage signal up to 2000V can be measured, and it has a bandwidth up to 1MHz.

The circuit of the utility model is mainly applied on the following boards of the analyzer:

a) Signal card 1 - excitation voltage, current conditioning card:

One high-voltage isolated AC and DC mixed-use high-voltage channel has 5 terminals, divided into four levels of 5V, 500V, 1000V, and 2000V; when in use, an appropriate range can be selected according to the actual situation. The input signal of this channel mainly measures the generator rotor voltage, regulator output voltage. One high-voltage isolated AC and DC mixed weak voltage channel with a range of ±100mV, used to measure generator rotor current and exciter excitation current.

b) Signal card 2 - general AC and DC voltage signal conditioning card:

Four ordinary AC and DC mixed channels, the measuring range is ±20V, there are four sets of signal terminals U1-U4, and the isolation voltage is 3000V.

c) Signal card 3 —— 4-20mA conditioning card:

There are 8 channels of 4-20mA signal input, the linearity can reach 0.2%, and the isolation voltage is 5000V.

The hardware of the upper computer is mainly composed of a portable notebook, which is the main carrier of the application software, and can be easily carried by the user for on-site operations.

The application software is installed on the notebook, and its main function is to display, record, analyze, process and output data, and it is the main interface for information communication with the operator. The application software receives the data from the lower computer, and processes the data so that it can intuitively and real-time display the information of various measurement signals on site through graphics, data, electronic instruments, electronic forms, etc.

The above is only a preferred specific embodiment of the utility model, but the scope of protection of the utility model is not limited thereto, and any skilled person familiar with the technical field can easily think of changes within the technical scope disclosed in the present invention Or replacement, all should be covered within the scope of protection of the present utility model.

Claims (4)

1. A measurement device for power AC analog signals based on a linear optocoupler, including a lower computer (1), an upper computer (2) and application software (3) equipped with modular functional hardware, and a lower computer (1) chassis The plug-in card connection is adopted inside, and the feature is that: the DC isolation circuit (4) of the lower computer (1) is provided with a linear optocoupler circuit (5). 2. The measuring device for power AC analog signal based on linear optocoupler according to claim 1, characterized in that: said linear optocoupler circuit (5) is an HCNR201 high-precision linear optocoupler circuit provided by Agilent. 3. The measurement device for power AC analog signal based on linear optocoupler according to claim 1, characterized in that: the linear optocoupler circuit (5) set in the lower computer (1) is set as the following board: a) Signal card 1 - excitation voltage, current conditioning card: One high-voltage isolated AC and DC mixed-use high-voltage channel has 5 terminals, divided into four levels of 5V, 500V, 1000V, and 2000V; when in use, an appropriate range can be selected according to the actual situation. The input signal of this channel mainly measures the generator rotor voltage, Regulator output voltage; one high-voltage isolated AC and DC mixed weak voltage channel, with a range of ±100mV, used to measure the generator rotor current and exciter excitation current; b) Signal card 2 - general AC and DC voltage signal conditioning card: Four ordinary AC and DC mixed channels, the measuring range is ±20V, there are four sets of signal terminals U1-U4, and the isolation voltage is 3000V; c) Signal card 3 —— 4-20mA conditioning card: There are 8 channels of 4-20mA signal input, the linearity can reach 0.2%, and the isolation voltage is 5000V. 4. The device for measuring power AC analog signals based on linear optocouplers according to claim 1, characterized in that: the host computer (2) is a portable notebook, and the application software (3) is installed on the notebook.