Multi-channel electric power analyzer with independent program control eight ranges in each channel

Abstract

The embodiment of the utility model provides a multi-channel electric power analyzer with each channel having independent program control eight ranges, and relates to the technical field of signal processing, the multi-channel electric power analyzer comprises a plurality of voltage and current signal processing plug-ins, an intelligent acquisition board and a data processor, each voltage and current signal processing plug-in is provided with four independent signal processing loops, the intelligent acquisition board is connected with the processor through the corresponding processing plug-in and is used for processing the input voltage and current signals into standard signals and outputting the standard signals to the intelligent acquisition board; the intelligent acquisition board is used for carrying out data sampling and caching on the standard signal and transmitting the standard signal to the terminal equipment; and the data processor is used for processing the data sampled by the intelligent acquisition board to obtain effective waveforms and concerned characteristic parameters. The embodiment of the utility model has the advantages of wide measurement range, high measurement precision, high signal bandwidth, high common-mode interference resistance and high-speed acquisition capability, effectively reduces the recording distortion problem of high-frequency or abrupt change signals, and improves the authenticity of data recording.

Description

Technical Field

[0001] The present application relates to the technical field of voltage and current signal data processing, and in particular to a multi-channel power analyzer with each channel having 8 independently programmable ranges. Background Art

[0002] The voltage and current data recorder and analyzer is a comprehensive power test instrument. It is widely used in power systems to record on-site voltage, current, power and other electrical quantities and has functions such as analysis and calculation, graphic processing, report generation and printing. However, due to many reasons, the current data recorder and analyzer has a single range or a very small number of ranges, a low bandwidth of the input signal processing circuit, and poor common-mode interference resistance. The single range or the very small number of ranges directly results in the poor adaptability of the instrument to on-site signals. Some on-site signals cannot be measured or it is difficult to select a suitable range to ensure measurement accuracy; the low bandwidth of the input signal processing circuit directly results in a large attenuation of high-frequency signals or steep-changing signals, large distortion of the measurement results, and the authenticity of the measurement results cannot be guaranteed; the poor ability to resist common-mode interference directly results in a large spatial interference of the signal during on-site measurement, especially the measurement of small signals, which is more seriously interfered. Summary of the invention

[0003] In view of this, the purpose of an embodiment of the present application is to provide a multi-channel power system data recorder and analyzer with independent programmable 8 ranges for each channel, so as to solve the problems of poor adaptability to field signals, low bandwidth and susceptibility to interference that affect measurement accuracy in current voltage and current data recorders and analyzers.

[0004] The technical solution of the present application for a multi-channel power analyzer with 8 independent programmable ranges per channel is:

[0005] A multi-channel power analyzer with 8 independent programmable ranges per channel, comprising: a plurality of signal processing plug-ins, an intelligent data acquisition board and a processor, wherein the intelligent data acquisition board is connected to the processor via the plurality of signal processing plug-ins;

[0006] Each signal processing plug-in has 4 independent signal processing loops, and each signal processing loop is provided with an independent program-controlled 8-range for receiving voltage and current signals and processing them into standard signals for output to the intelligent data acquisition board;

[0007] An intelligent data acquisition board, used for receiving and performing data sampling and caching on the standard signal, and sending the obtained converted voltage and current signals to a terminal device;

[0008] The data processor is used to receive the converted voltage and current signals and perform data processing and analysis to obtain effective waveforms and calculate characteristic parameters concerned by different tests.

[0009] The above-mentioned multi-channel power analyzer has 8 independently programmable ranges for each channel, wherein each of the signal processing plug-ins has 4 independent signal processing loops, and each signal processing loop includes: a range controller and a range control loop connected to the range controller, and the range controller is used to receive the range control command set according to the input voltage and current signals, and send the range control instruction to the range control loop to adjust the range gear of the channel corresponding to the signal processing plug-in.

[0010] The above-mentioned multi-channel power analyzer has 8 independently programmable ranges for each channel, wherein each of the range control loops includes: a voltage divider circuit, an instrument programmable differential amplifier and a secondary programmable amplifier; the voltage divider circuit includes a relay for receiving range control instructions and determining the voltage divider ratio of the channel corresponding to the signal processing plug-in by controlling the opening / closing of the relay; the voltage divider circuit is respectively connected to the instrument programmable differential amplifier and the secondary programmable amplifier, and is used to comprehensively determine the range gear of the corresponding channel according to the voltage divider ratio and the amplification factors of the instrument programmable differential amplifier and the secondary programmable amplifier.

[0011] The above-mentioned multi-channel power analyzer has each channel with independently programmable 8 ranges, wherein the multiple channels are all provided with different input impedances and / or different amplification factors so that different channels have different range gears.

[0012] The above-mentioned multi-channel power analyzer has 8 independently programmable ranges for each channel, wherein each channel is also provided with an overvoltage protection circuit, and the overvoltage protection circuit is connected to the range controller; the overvoltage protection circuit is used to compare the voltage and current signals input into the range controller, and when the input signal exceeds the preset range, the overvoltage protection signal is output to switch the range of the channel to the highest range to prevent the channel from being damaged due to overvoltage.

[0013] The above-mentioned multi-channel power analyzer with each channel having 8 independent programmable ranges, wherein the overvoltage protection circuit includes:

[0014] A first resistor having one end connected to the range control loop;

[0015] A comparator connected to the other end of the first resistor, the comparator being used to compare the voltage and current signals input into the range controller, and outputting an overvoltage protection signal when the voltage and current signals exceed a preset value;

[0016] A second resistor, one end of which is connected to the first resistor and the comparator respectively, and the other end of which is grounded.

[0017] The above-mentioned multi-channel power analyzer has each channel with independent programmable 8 ranges, wherein each of the overvoltage protection circuits is also connected to an intelligent data acquisition board and outputs an overvoltage protection alarm signal when the overvoltage protection is activated.

[0018] The above-mentioned multi-channel power analyzer has 8 independently programmable ranges for each channel, wherein the instrument programmable differential amplifier is connected to the range controller through two pins, and the secondary programmable amplifier is connected to the range controller through three pins.

[0019] The above-mentioned multi-channel power analyzer has 8 independently programmable ranges for each channel, wherein each signal processing plug-in also includes a signal processing circuit, which is connected to the range control circuit and is used to process the voltage and current signals into the standard signals.

[0020] The above-mentioned multi-channel power analyzer has 8 independent programmable ranges for each channel, wherein each signal processing loop includes an isolation amplifier, a signal amplifier and a low-pass filter connected in sequence.

[0021] The independently programmable 8-range multi-channel voltage and current recording and analyzing instrument provided in the embodiment of the present application adopts the instrument-use programmable differential amplifier AD8253 with a bandwidth of 3MHz as the front-stage interface chip, adopts the operational amplifiers OPA4227 and OPA2227 with a bandwidth of 8MHz as the operational amplifiers of the signal processing process, adopts the AMC1301 with a bandwidth of 200kHz as the isolation amplifier, and is equipped with a 4th-order Butterworth low-pass filter with a cut-off frequency of 50kHz. The final signal conversion bandwidth is 50kHz, which solves the problem that the signal bandwidth of the voltage signal conversion loop of the power system data recording and analyzing instrument is insufficient, and the high-frequency or steep-change signal is severely attenuated, resulting in serious final record distortion, thereby improving the signal bandwidth of the data recording instrument, reducing the recording distortion of high-frequency or steep-change signals on site, and improving the authenticity of the data recording.

[0022] In addition, a high-precision symmetrical and balanced front-stage differential voltage divider circuit is used, and the instrument-use program-controlled differential amplifier AD8253 with a common-mode interference suppression ratio of 100dB is used as the front-stage input interface chip, achieving a common-mode interference suppression ratio of 80dB. It better solves the problems of insufficient common-mode interference resistance of the voltage signal conversion circuit of the power system data recording and analysis instrument, waveform distortion caused by interference of small signals, and small fluctuations in the measured value of the power frequency signal caused by the power frequency interference of the field space, thereby improving the data recorder's ability to resist common-mode interference and ultimately improving the accuracy of data recording.

[0023] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 The logical principle diagram of the range control loop of a multi-channel power analyzer of the present application in which each channel has 8 independently programmable ranges is shown.

[0026] Figure 2 A schematic diagram of a range control circuit and a signal processing circuit in each channel of a multi-channel power analyzer of the present application in which each channel has 8 independently programmable ranges is shown.

[0027] Figure 3 The schematic diagram of the overvoltage protection circuit in each channel of a multi-channel power analyzer with 8 independent programmable ranges per channel according to the present application is shown.

[0028] Figure 4 The overall logic diagram of a multi-channel power analyzer of the present application is shown, in which each channel has 8 independently programmable ranges. DETAILED DESCRIPTION

[0029] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0030] Most products only consider the use of a certain working condition or a part of a specific working condition, and each input channel only considers the processing of a certain specific signal or a part of a typical signal. For example, the voltage input channel of most products is only for the PT secondary voltage, and the input quantity is set to a single AC150V; the current input channel is only for the CT secondary current, and the input range is set to a single AC5A or AC1A; this input mode, when it is necessary to measure AC380V or higher voltage, the signal cannot be connected, and a voltage plug-in with a higher range needs to be configured. Although some products also use multi-range mode, the number of ranges is small, only 2 or 4 ranges, and the difference between adjacent ranges is large. For example, the ranges of a 4-range instrument are ±2000V (AC1400V), ±1000V (AC700V), ±200V (AC140V), and ±20V (AC140V). In this way, when measuring the PT secondary voltage, whether it is AC100V line voltage or AC57.735V phase voltage, only ±20 can be selected. 0V (AC140V) range, so when measuring AC57.735V phase voltage, the actual signal is always below 40% of the range used, and the relative accuracy of the measurement is half that of the ±100V (AC70V) range of this example. Similarly, when measuring DC24V signal, only ±200V (AC140V) range can be selected, and the actual signal is only about 12% of the range, and the actual measurement accuracy is 4 times lower than that of the ±50V (AC35V) range of this example. In short, most of the current power system data recording and analysis instruments have the problem of insufficient input signal range, insufficient adaptability to field signals, and greatly limited application occasions.

[0031] The present application discloses a multi-channel power analyzer with 8 independent programmable ranges for each channel, including multiple signal processing plug-ins, an intelligent data acquisition board and a processor, etc. Multiple voltage and current signal processing plug-ins are provided, and each channel has 8 independent programmable ranges, which are used to process the voltage and current signals of the power system of the input device into standard signals suitable for AD conversion. The intelligent data acquisition board is composed of 24 synchronously collected AD devices, a logic controller and an embedded industrial computer system, which is used to sample and cache the standard signals processed by the voltage and current signal processing plug-ins and transmit them to terminal devices such as laptops via 1000M Ethernet. The processor, such as the embedded computing unit, is used to process the voltage and current sampled by the data conditioning high-speed acquisition board to extract effective waveform data, and transmit the effective waveform data processed by the embedded computing unit to the client computer via Ethernet for further data processing and waveform display. The power management unit is used to power the data conditioning high-speed acquisition board and the embedded computing unit.

[0032] Among them, each of the signal processing plug-ins has 4 independent signal processing loops, and each signal processing loop includes: a range controller and a range control loop connected to the range controller. The range controller is used to receive the range control command set according to the input voltage and current signals, and send the range control instruction to the range control loop to adjust the range gear of the channel corresponding to the signal processing plug-in.

[0033] In a preferred embodiment, each of the range control loops includes: a voltage divider circuit, an instrument programmable differential amplifier and a secondary programmable amplifier; the voltage divider circuit includes a relay for receiving a range control instruction and determining the input impedance and voltage divider ratio of the channel corresponding to the signal processing plug-in by controlling the opening / closing of the relay; the voltage divider circuit is respectively connected to the instrument programmable differential amplifier and the secondary programmable amplifier, and is used to comprehensively determine the range gear of the corresponding channel according to the voltage divider ratio and the amplification factors of the instrument programmable differential amplifier and the secondary programmable amplifier.

[0034] like Figures 1 to 4 As shown, when an external voltage or current signal is input to the corresponding channel, the programmable logic controller adjusts the input impedance and the voltage divider ratio of the voltage divider circuit by controlling the opening or closing of two nodes of a relay according to the size of the input voltage or current. In addition, the programmable logic controller simultaneously adjusts the amplification factors of the instrument programmable differential amplifier and the secondary programmable amplifier. The instrument programmable differential amplifier has four amplification factors of 1, 10, 100, and 1000, and the secondary programmable amplifier has eight amplification factors. Five amplification factors of 1, 1 / 2, 1 / 2.5, 1 / 5, and 1 / 10 are actually used, thereby comprehensively adjusting the range gear of the channel. During on-site measurement, the most appropriate range unit can be selected according to the size of the actual signal, thereby reducing the relative error of the measurement and improving the accuracy of the detection.

[0035] like Figure 3 As shown, in order to prevent the small range from being burned out due to excessive input voltage or current, an overvoltage protection circuit is also provided on each channel. The comparator of the overvoltage protection circuit is used to compare the voltage or current value of the input channel. When the input voltage or current exceeds 1.5 times of the rated voltage or rated current, it is determined that the input voltage or current is too large, and the comparator sends an overvoltage protection signal. After receiving the overvoltage protection signal, the range controller directly adjusts the range of the channel to the highest gear, effectively avoiding damage to components due to excessive input voltage or current.

[0036] Due to the use of plug-in mode, the analog signal input plug-in is flexible in configuration, and each channel has 8 independently programmable ranges. The instrument can not only flexibly configure the analog signal input plug-in according to the requirements of the data recording instrument input channel for different characteristic signals of various professions, but also select the appropriate range according to the characteristics of the input signal during field tests. It can adapt well to various signals on the power system site and realize real-time data collection, analysis and storage of power system field tests.

[0037] In addition, with the automatic plug-in recognition function, the analog signal input plug-in can be flexibly configured according to the requirements of different professional and characteristic signals for the input channel of the data recording instrument, thereby improving the flexibility of instrument configuration.

[0038] By introducing the programmable 8-range mechanism, the high-voltage signal processing card realizes that each channel can freely program-control the switching control between eight AC and DC voltage ranges: ±2000V (AC1400V), ±1000V (AC700V), ±400V (AC280V), ±200V (AC140V), ±100V (AC70V), ±50V (AC35V), ±20V (AC14V), and ±10V (AC7V); the low-voltage signal processing card realizes that each channel can freely program-control the switching control between eight AC and DC voltage ranges: ±200V (AC140V), ±100V (AC70V), ±20V (AC14V), ±10V (AC7V), ±5V (AC3.5V), ±2V The eight-speed AC / DC voltage and current universal measuring ranges of ±100mV (AC1A), ±500mV (AC5A), and ±100mV (AC1A) can be freely switched between programmable ranges. The coordinated use of the two plug-ins ensures that the level difference between adjacent measuring ranges from ±2000V (AC1400V) to ±1V (AC0.7V) is between 2 times or 2.5 times. That is, when measuring the actual signal of ±2000V (AC1400V) to ±1V (AC0.7V) on site, a suitable measuring range not greater than 2.5 times or 2 times the amplitude of the signal itself can be selected, which can well ensure the relative accuracy of on-site measurement and solve the shortcomings of limited measuring range of each channel and insufficient signal adaptability.

[0039] The instrument program-controlled differential amplifier AD8253 is selected as the input interface chip, OPA4227 and OPA2227 are used as signal processing amplifiers, high-precision and high-stability resistors are used as voltage divider resistors and signal processing loop resistors, and high-precision AMC1301 is used as an isolation amplifier, so that the utility model achieves excellent isolation conversion effects with conversion accuracy better than 0.05%, linearity better than 0.02%, and temperature coefficient better than 30PPM. The problem of insufficient accuracy of the voltage signal conversion loop of the power system data recording and analysis instrument is solved, thereby improving the acquisition and recording accuracy of the power system data recording and analysis instrument, ensuring that the data recording instrument has good acquisition accuracy in a wider signal range, and improving the adaptability of the data recorder to field signals.

[0040] The instrument-used programmable differential amplifier AD8253 with a bandwidth of 3MHz is used as the front-stage interface chip, the operational amplifiers OPA4227 and OPA2227 with a bandwidth of 8MHz are used as operational amplifiers for the signal processing process, and the AMC1301 with a bandwidth of 200kHz is used as the isolation amplifier. It is also equipped with a 4th-order Butterworth low-pass filter with a cut-off frequency of 50kHz. The final signal conversion bandwidth is 50kHz, which solves the problems of insufficient signal bandwidth of the voltage signal conversion loop of the power system data recording and analysis instrument, and serious attenuation of high-frequency or steep-change signals causing serious final record distortion, thereby improving the signal bandwidth of the data recording instrument, reducing the recording distortion of high-frequency or steep-change signals on site, and improving the authenticity of the data records.

[0041] The high-precision symmetrical and balanced front-stage differential voltage divider circuit is adopted, and the instrument-use program-controlled differential amplifier AD8253 with a common-mode interference suppression ratio of 100dB is used as the front-stage input interface chip, achieving a common-mode interference suppression ratio of 80dB. It better solves the problems of insufficient common-mode interference resistance of the voltage signal conversion circuit of the power system data recording and analysis instrument, waveform distortion caused by interference of small signals, and small fluctuations in the measured value of the power frequency signal caused by the power frequency interference of the field space, thereby improving the data recorder's ability to resist common-mode interference and ultimately improving the accuracy of data recording.

[0042] The 10MΩ and 1MΩ input impedances at high and low ranges effectively solve the problem of insufficient input impedance of the voltage signal conversion circuit of the power system data recorder and analyzer, greatly reducing the influence of the instrument on the measured signal, thereby greatly improving the overall performance of the power system data recorder and analyzer using the utility model as the signal input interface.

[0043] The hardware overvoltage protection circuit solves the problem that small-range channels are easily burned out, and better solves the safety problem of the instrument.

[0044] This application introduces a programmable 8-range mechanism to solve the problem of insufficient input signal range of the input channel and too large difference between available ranges. The programmable range circuit is implemented by a set of voltage divider circuits that can set different voltage divider ratios, a differential amplifier for programmable instruments, and a secondary programmable amplifier. In order to meet different needs on site, two signal range signal processing plug-ins are set, one is a pure voltage type high voltage voltage processing plug-in, and the other is a low voltage signal processing plug-in that takes into account lower voltage and transformer (transmitter) output voltage. The circuit schematics of the two signal processing plug-ins are shown in Figure 1 and Figure 2 .

[0045] The combination of pure voltage type high voltage processing plug-in voltage divider circuit and programmable amplifier realizes the following 8 ranges:

[0046] (a) Working principle of gear position 1 (±2000V range): The contacts of relays J1.1 and J1.2 are not closed, and the voltage division ratio is 10M / 5K=2000:1. At this time, when the voltage of ±2000V is input, the voltage on R3 and R3A is ±1V, the gain of the differential amplifier used by the program controller is 1, and the gain of the secondary program amplifier is 10:1. The final nominal voltage input to the isolation amplifier is ±0.1V, and finally processed into a standard signal of ±5V after isolation amplification and low-pass filtering, and sent to the AD converter of the subsequent stage, and the corresponding range is ±2000V;

[0047] (b) Working principle of gear 2 (±1000V range): The contacts of relays J1.1 and J1.2 are not closed, and the voltage division ratio is 10M / 5K=2000:1. At this time, when the voltage of ±1000V is input, the voltage on R3 and R3A is ±0.5V, the gain of the differential amplifier used by the program controller is 1, and the gain of the secondary program amplifier is 5:1. The final nominal voltage input to the isolation amplifier is ±0.1V, and finally processed into a standard signal of ±5V after isolation amplification and low-pass filtering, and sent to the AD converter of the subsequent stage, and the corresponding range is ±1000V;

[0048] (c) Working principle of gear position 3 (±400V range): The contacts of relays J1.1 and J1.2 are not closed, and the voltage division ratio is 10M / 5K=2000:1. At this time, when the voltage of ±400V is input, the voltage on R3 and R3A is ±0.2V, the gain of the differential amplifier used by the program controller is 1, and the gain of the secondary program amplifier is 2:1. The final nominal voltage input to the isolation amplifier is ±0.1V, and finally processed into a standard signal of ±5V after isolation amplification and low-pass filtering, and sent to the AD converter of the subsequent stage, and the corresponding range is ±400V;

[0049] (d) Working principle of gear 4 (±200V range): When the contacts of relays J1.1 and J1.2 are not closed, the voltage division ratio is 10M / 5K=2000:1. At this time, when the voltage of ±200V is input, the voltage on R3 and R3A is ±0.1V. The gain of the differential amplifier used by the program controller is 1, and the gain of the secondary program amplifier is 1:1. The final nominal voltage input to the isolation amplifier is ±0.1V. Finally, after isolation amplification and low-pass filtering, it is processed into a standard signal of ±5V and sent to the AD converter of the subsequent stage. The corresponding range is ±200V.

[0050] (e) Working principle of gear position 5 (±100V range): The contacts of relays J1.1 and J1.2 are closed, and the voltage division ratio is 500K / 5K=100:1. At this time, when the voltage of ±100V is input, the voltage on R3 and R3A is ±1V, the amplification factor of the differential amplifier used by the program controller is 1, and the amplification factor of the secondary program-controlled amplifier is 10:1. The final nominal voltage input to the isolation amplifier is ±0.1V, and finally processed into a standard signal of ±5V after isolation amplification and low-pass filtering, and sent to the AD converter of the subsequent stage, and the corresponding range is ±100V;

[0051] (f) Working principle of gear 6 (±50V range): The contacts of relays J1.1 and J1.2 are closed, and the voltage division ratio is 500K / 5K=100:1. At this time, when the voltage of ±50V is input, the voltage on R3 and R3A is ±0.5V, the amplification factor of the differential amplifier used by the program controller is 1, and the amplification factor of the secondary program-controlled amplifier is 5:1. The final nominal voltage input to the isolation amplifier is ±0.1V, and finally processed into a standard signal of ±5V after isolation amplification and low-pass filtering, and sent to the AD converter of the subsequent stage, and the corresponding range is ±50V;

[0052] (g) Working principle of gear position 7 (±20V range): The contacts of relays J1.1 and J1.2 are closed, and the voltage division ratio is 500K / 5K=100:1. At this time, when the voltage of ±20V is input, the voltage on R3 and R3A is ±0.2V, the gain of the differential amplifier used by the program controller is 1, and the gain of the secondary program-controlled amplifier is 2:1. The final nominal voltage input to the isolation amplifier is ±0.1V, and finally processed into a standard signal of ±5V after isolation amplification and low-pass filtering, and sent to the AD converter of the subsequent stage, and the corresponding range is ±20V;

[0053] (h) Working principle of gear position 8 (±10V range): The contacts of relays J1.1 and J1.2 are closed, and the voltage division ratio is 500K / 5K=100:1. At this time, when the voltage of ±10V is input, the voltage on R3 and R3A is ±0.1V, the gain of the differential amplifier used by the program controller is 1, and the gain of the secondary program amplifier is 1:1. The final nominal voltage input to the isolation amplifier is ±0.1V, and finally processed into a standard signal of ±5V after isolation amplification and low-pass filtering, and sent to the AD converter of the subsequent stage, and the corresponding range is ±10V;

[0054] As described above, the pure voltage type high voltage processing plug-in of the utility model realizes the control of 8 AC and DC universal signal ranges of ±2000V (AC1400V), ±1000V (AC700V), ±400V (AC280V), ±200V (AC140V), ±100V (AC70V), ±50V (AC35V), ±20V (AC14V), and ±10V (AC7V) by comprehensive control of the voltage divider ratio of the voltage divider circuit, the amplification factor of the differential amplifier used by the program controller, and the amplification factor of the secondary program-controlled amplifier. These 8 ranges can adapt to most voltage signals in the field test of the power system. In the field test, the ±2000V (AC1400V) range can well adapt to the signal input of the generator excitation voltage of more than 1 kilovolt; the ±1000V (AC700V) range can well adapt to the AC690V terminal voltage of the wind turbine and the AC380V system line voltage; the ±400V (AC280V) range can well adapt to the AC220 phase voltage of the AC380V system, the bus voltage of the photovoltaic power station, and the DC 220V operating voltage input of the power plant; the ±200V (AC140V) range can well adapt to the AC220 phase voltage of the AC380V system, the bus voltage of the photovoltaic power station, and the DC 220V operating voltage of the power plant. It can adapt to the line voltage of PT secondary and the input of DC 110V operating voltage of power plant; the ±100V (AC70V) range can well adapt to the input of PT secondary phase voltage; the ±50V (AC35V) range can well adapt to the DC48V power supply system; the ±20V (AC14V) range can well adapt to the output signals of various transmitters with DC24V power supply; the ±10V (AC7V) range can well adapt to the voltage and small AC voltage signal input of various voltage output transmitters with ±10V and ±5V output range.

[0055] The combination of the low voltage signal processing plug-in voltage divider circuit and the programmable amplifier realizes the following 8 ranges:

[0056] (i) Working principle of gear position 1 (±200V range): The contacts of relays J1.1 and J1.2 are not closed, and the voltage division ratio is 1M / 5K=200:1. At this time, when the voltage of ±200V is input, the voltage on R3 and R3A is ±1V, the gain of the differential amplifier used by the program controller is 1, and the gain of the secondary program amplifier is 10:1. The final nominal voltage input to the isolation amplifier is ±0.1V, and finally processed into a standard signal of ±5V after isolation amplification and low-pass filtering, and sent to the AD converter of the subsequent stage, and the corresponding range is ±200V;

[0057] (j) Working principle of gear 2 (±100V range): The contacts of relays J1.1 and J1.2 are not closed, and the voltage division ratio is 1M / 5K=200:1. At this time, when the voltage of ±100V is input, the voltage on R3 and R3A is ±0.5V, the gain of the differential amplifier used by the program controller is 1, and the gain of the secondary program amplifier is 5:1. The final nominal voltage input to the isolation amplifier is ±0.1V, and finally processed into a standard signal of ±5V after isolation amplification and low-pass filtering, and sent to the AD converter of the subsequent stage, and the corresponding range is ±100V;

[0058] (k) Working principle of gear position 3 (±20V range): The contacts of relays J1.1 and J1.2 are not closed, and the voltage division ratio is 1M / 5K=200:1. At this time, when the voltage of ±20V is input, the voltage on R3 and R3A is ±0.1V, the gain of the differential amplifier used by the program controller is 1, and the gain of the secondary program-controlled amplifier is 1:1. The final nominal voltage input to the isolation amplifier is ±0.1V, and finally processed into a standard signal of ±5V after isolation amplification and low-pass filtering, and sent to the AD converter of the subsequent stage, and the corresponding range is ±20V;

[0059] (l) Working principle of gear 4 (±10V range): The contacts of relays J1.1 and J1.2 are not closed, and the voltage division ratio is 1M / 5K=200:1. At this time, when the voltage of ±10V is input, the voltage on R3 and R3A is ±0.05V, the gain of the differential amplifier used by the program controller is 10, and the gain of the secondary program amplifier is 5:1. The final nominal voltage input to the isolation amplifier is ±0.1V, and finally processed into a standard signal of ±5V after isolation amplification and low-pass filtering, and sent to the AD converter of the subsequent stage, and the corresponding range is ±10V;

[0060] (m) Working principle of gear position 5 (±5V range): The contacts of relays J1.1 and J1.2 are not closed, and the voltage division ratio is 1M / 5K=200:1. At this time, when the ±5V voltage is input, the voltage on R3 and R3A is ±0.025V, the amplification factor of the differential amplifier used by the program controller is 10, and the amplification factor of the secondary program-controlled amplifier is 2.5:1. The final nominal voltage input to the isolation amplifier is ±0.1V, and finally processed into a ±5V standard signal after isolation amplification and low-pass filtering, and sent to the AD converter of the subsequent stage, and the corresponding range is ±5V;

[0061] (n) Working principle of gear position 6 (±2V range): The contacts of relays J1.1 and J1.2 are not closed, and the voltage division ratio is 1M / 5K=200:1. At this time, when the ±2V voltage is input, the voltage on R3 and R3A is ±0.01V, the amplification factor of the differential amplifier used by the program controller is 10, and the amplification factor of the secondary program-controlled amplifier is 1:1. The final nominal voltage input to the isolation amplifier is ±0.1V, and finally processed into a ±5V standard signal after isolation amplification and low-pass filtering, and sent to the AD converter of the subsequent stage, and the corresponding range is ±2V;

[0062] (o) Working principle of gear position 7 (±500mV range): The contacts of relays J1.1 and J1.2 are closed, and the voltage division ratio is 25K / 5K=5:1. At this time, when the voltage of ±500mV is input, the voltage on R3 and R3A is ±100mV, the amplification factor of the differential amplifier used by the program controller is 10, and the amplification factor of the secondary program-controlled amplifier is 10:1. The final nominal voltage input to the isolation amplifier is ±0.1V, and finally processed into a standard signal of ±500mV after isolation amplification and low-pass filtering, and sent to the AD converter of the subsequent stage, and the corresponding range is ±500mV;

[0063] (p) Working principle of gear position 8 (±100mV range): The contacts of relays J1.1 and J1.2 are closed, and the voltage division ratio is 25K / 5K=5:1. At this time, when the voltage of ±100mV is input, the voltage on R3 and R3A is ±20mV, the gain of the differential amplifier used by the program controller is 10, and the gain of the secondary program-controlled amplifier is 2:1. The final nominal voltage input to the isolation amplifier is ±0.1V, and finally it is processed into a standard signal of ±5V after isolation amplification and low-pass filtering, and sent to the AD converter of the subsequent stage, and the corresponding range is ±100mV.

[0064] As described above, the utility model realizes the control of 8 AC and DC universal signal ranges of ±200V (AC140V), ±100V (AC70V), ±20V (AC14V), ±10V (AC7V), ±5V (AC3.5V), ±2V (AC1.4V), ±500mV (AC305mV), and ±100mV (AC70mV) by comprehensive control of the voltage divider ratio of the voltage divider circuit, the amplification factor of the differential amplifier used in the program controller, and the amplification factor of the secondary program-controlled amplifier. These 8 ranges can adapt to most voltage signals in the field test of the power system. In the field test, the ±200V (AC140V) range can well adapt to the PT secondary line voltage and the input of the DC 110V operating voltage of the power plant; the ±100V (AC70V) range can well adapt to the PT secondary phase voltage input and the DC48V power supply system; the ±20V (AC14V) range can well adapt to the output signals of various transmitters with DC24V power supply; the ±10V (AC7V) range can well adapt to the small AC and DC voltage signal input of various voltage output type transmitters with ±10V output range; the ±5V (AC3.5V) range can well adapt to the small AC and DC voltage signal input of various voltage output type transmitters with ±5V output range; the ±2.0V (AC1.4V) range can well adapt to various voltage output types from several hundred amperes to The AC and DC voltage signal input output by the AC and DC current sensor of one or two thousand amperes; the ±500mV (AC350mV) range can be well matched with the AC5A / ±500mV (or AC50A / ±500mV, etc.) clamp-type transformer customized by our company, which can measure the AC current within 5A (or 50A), and can also adapt to the AC and DC voltage signal input output by various AC and DC current sensors of several hundred amperes; the ±100mV (AC70mV) range can be well matched with the AC5A / ±500mV (or AC50A / ±500mV, etc.) clamp-type transformer customized by our company, which can measure the AC current within 1A (or 10A), and can also adapt to the AC and DC voltage signal input output by various AC and DC current sensors of several tens of amperes.

[0065] In addition, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

Claims

1. A multi-channel power analyzer with 8 independent programmable ranges for each channel, characterized in that: include: A plurality of signal processing plug-ins, an intelligent data acquisition board and a processor, wherein the intelligent data acquisition board is connected to the processor via the plurality of signal processing plug-ins; Each signal processing plug-in has 4 independent signal processing loops, and each signal processing loop is provided with an independent program-controlled 8-range for receiving voltage and current signals and processing them into standard signals for output to the intelligent data acquisition board; An intelligent data acquisition board, used for receiving and performing data sampling and caching on the standard signal, and sending the obtained converted voltage and current signals to a terminal device; The data processor is used to receive the converted voltage and current signals and perform data processing and analysis to obtain effective waveforms and calculate characteristic parameters concerned by different tests.

2. The multi-channel power analyzer with 8 independent programmable ranges for each channel according to claim 1, characterized in that: Each of the signal processing plug-ins has four independent signal processing loops, and each signal processing loop includes: a range controller and a range control loop connected to the range controller. The range controller is used to receive a range control command set according to the input voltage and current signals, and send a range control instruction to the range control loop to adjust the range gear of the channel corresponding to the signal processing plug-in.

3. The multi-channel power analyzer with 8 independent programmable ranges for each channel according to claim 2, characterized in that: Each of the range control loops includes: a voltage divider circuit, an instrument programmable differential amplifier and a secondary programmable amplifier; the voltage divider circuit includes a relay for receiving a range control instruction and determining the voltage divider ratio of the channel corresponding to the signal processing plug-in by controlling the opening / closing of the relay; the voltage divider circuit is respectively connected to the instrument programmable differential amplifier and the secondary programmable amplifier, and is used to comprehensively determine the range gear of the corresponding channel according to the voltage divider ratio and the amplification factors of the instrument programmable differential amplifier and the secondary programmable amplifier.

4. The multi-channel power analyzer with 8 independent programmable ranges for each channel according to claim 3, characterized in that: The multiple channels are all provided with different input impedances and / or different amplification factors, so that different channels have different range gears.

5. The multi-channel power analyzer with 8 independent programmable ranges for each channel according to claim 2, characterized in that: Each channel is also provided with an overvoltage protection circuit, which is connected to the range controller; the overvoltage protection circuit is used to compare the voltage and current signals input into the range controller, and when the input signal exceeds the preset range, output an overvoltage protection signal to switch the range of the channel to the highest range to prevent the channel from being damaged due to overvoltage.

6. The multi-channel power analyzer with 8 independent programmable ranges for each channel according to claim 5, characterized in that: The overvoltage protection circuit comprises: A first resistor having one end connected to the range control loop; A comparator connected to the other end of the first resistor, the comparator being used to compare the voltage and current signals input into the range controller, and outputting an overvoltage protection signal when the voltage and current signals exceed a preset value; A second resistor, one end of which is connected to the first resistor and the comparator respectively, and the other end of which is grounded.

7. The multi-channel power analyzer with 8 independent programmable ranges for each channel according to claim 5, characterized in that: Each of the overvoltage protection circuits is also connected to an intelligent data acquisition board and outputs an overvoltage protection alarm signal when the overvoltage protection is activated.

8. The multi-channel power analyzer with 8 independent programmable ranges for each channel according to claim 3, characterized in that: The instrument program-controlled differential amplifier is connected to the range controller via two pins, and the secondary program-controlled amplifier is connected to the range controller via three pins.

9. The multi-channel power analyzer with 8 independent programmable ranges for each channel according to any one of claims 1 to 8, characterized in that: Each signal processing plug-in further includes a signal processing circuit, which is connected to the range control circuit and is used to process the voltage and current signals into the standard signals.

10. The multi-channel power analyzer with 8 independent programmable ranges for each channel according to claim 9, characterized in that: Each signal processing loop includes an isolation amplifier, a signal amplifier and a low-pass filter which are connected in sequence.

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