CN203054128U - Electric power parameter detection system - Google Patents

Abstract

The utility model discloses a power parameter detection system, which comprises: a sensor module connected to the power system; an analog switch circuit, an amplifying circuit and a low-pass filter circuit sequentially connected to the output end of the sensor module; used for collecting the voltage of each phase of the power system , a data acquisition circuit for current data, the data acquisition circuit is connected to the output end of the low-pass filter circuit; a computer for calculating various power parameters of the power system according to the voltage and current data of each phase, the computer is connected to the The data acquisition circuit described above. The utility model collects the voltage and current signals of each phase collected by the voltage transformer and the current transformer through a data acquisition card, and the computer calculates each power parameter of the power system according to the voltage and current signal of each phase, and the detection of the power parameter is accurate. It provides an objective basis for measuring the power quality of the power system, and has the advantages of simple structure and strong practicability.

Description

Power parameter detection system

technical field

The utility model relates to a detection system, in particular to a power parameter detection system for measuring power quality.

Background technique

With the development of society, power quality issues are more and more concerned by power companies and users. Power quality issues are related to the interests of all parties. Therefore, real-time online detection of power quality is an inevitable trend.

The premise of measuring the quality of electric energy and the improvement of electric energy and quality is the detection of electric parameter indicators. The traditional power parameter index detection device uses analog signal analysis. Different power parameter index detection uses different instruments and meters, such as: traditional current and voltage meters, power meters, frequency meters, harmonic meters, three-phase unbalance meters, Voltage fluctuation and flicker, etc., the disadvantages of this kind of detection device are that the measurement is cumbersome, the instrument has poor versatility, and the degree of automation is low.

With the widespread development and use of a new generation of digital instruments with microprocessors and DSP as the core, many domestic power quality detection devices are also designed and developed in this way. This type of detection instrument is fixed, so it is limited by the processing speed and capacity of the hardware in terms of signal processing and data storage. The disadvantages of this type of detector are that the data exchange and sharing are not strong, the flexibility is poor, the analysis algorithm is simple, the data storage is small, and the upgrade is difficult.

Utility model content

In order to overcome the defects of the prior art, the utility model proposes a power parameter detection system for measuring power quality with accurate detection and strong practicability.

The utility model is realized by adopting the following technical solutions: a power parameter detection system, which includes: a sensor module connected to the power system; an analog switch circuit, an amplifying circuit and a low-pass filter circuit sequentially connected to the output end of the sensor module; A data acquisition circuit for the voltage and current data of each phase of the power system, the data acquisition circuit is connected to the output end of the low-pass filter circuit; a computer for calculating various power parameters of the power system according to the voltage and current data of each phase, The computer is connected to the data acquisition circuit.

Wherein, the sensor module includes a voltage transformer and a current transformer respectively connected to the power system.

Wherein, the analog switch circuit is a 16-channel/dual 8-channel analog multiplexer, and four control ports of the analog multiplexer are connected to the data acquisition circuit.

Wherein, the low-pass filter circuit is a fourth-order Butterworth low-pass filter with programmable cut-off frequency.

Wherein, the data acquisition circuit is connected to the computer through a PCI bus interface.

Compared with the prior art, the utility model has the following beneficial effects:

The utility model can collect the voltage and current signals of each phase collected by the voltage transformer and the current transformer through a data acquisition card, and the computer can calculate each power parameter index of the power system according to the voltage and current signals of each phase, and detect the power parameters. Accurate, it provides an objective basis for measuring the power quality of the power system, and has the advantages of simple structure and strong practicability.

Description of drawings

Fig. 1 is the structural representation of the utility model.

Figure 2 is a schematic circuit diagram of a current transformer

Fig. 3 is a schematic circuit diagram of an analog switch.

Fig. 4 is a schematic circuit diagram of the amplifying circuit.

Detailed ways

As shown in Figure 1, the utility model proposes a power parameter detection system for measuring power quality with accurate detection and strong practicability, which includes: a sensor module 1 connected to the power system, including a voltage transformer 11 and a current transformer Device 12 (the circuit diagram of current transformer 12 is as shown in Figure 2); Connect the output terminal of voltage transformer 11 and the analog switch circuit 2 of the output terminal of current transformer 12, amplifying circuit 3, low-pass filter circuit 4 and data acquisition successively circuit 5; and a computer 6 connected to the data acquisition circuit 5.

The power parameters of the power system are converted and amplified by the voltage transformer 11 and the current transformer 12. The six-way small voltage signals are input to the dual-channel 16-way/double 8-way analog switch circuit 2, and each signal is output in pairs, and the signal is carried out by the amplifier circuit 3. The gain amplification processing is performed by the low-pass filter circuit 4 and then transmitted to the data acquisition circuit 5 .

Among them, the analog switch circuit 2 is realized by the 16-channel/dual-8-channel, low-leakage, CMOS analog multiplexer AD7507 produced by American AD Company, and outputs the voltage signals output by the sensor module 1 to the amplifier circuit 3 in pairs. The circuit diagram of the analog switch circuit 2 is as shown in Figure 3. Three channel selection terminals and one enabling terminal control the acquisition of two signals such as Ua, Ub, Uc, Ia, Ib, and Ic. Therefore, a total of two signals from the data acquisition circuit 5 introduces four control ports D0, D1, D2 and D3.

As shown in Figure 4, the amplifier circuit 3 is a high-precision, high-performance programmable gain amplifier circuit that can automatically adjust the magnification factor. It adopts a software programmable gain amplifier (SPGA, Software Programmable Gain Amplifier) with excellent performance produced by American AD Company. Chip AD526CD realizes program-controlled gain control. A ₂ port, A ₁ port and A ₀ port of the AD526CD chip are connected to the data acquisition circuit 5, and the different numerical values of the A ₂ port, the A ₁ port and the A ₀ port of the AD526CD chip are determined by the computer 6 through the data acquisition circuit 5 to determine the AD526CD chip of magnification.

And the low-pass filter circuit 4 adopts the fourth-order Butterworth (Butterworth) low-pass filter with programmable cut-off frequency, and sends a signal to the data acquisition circuit 5 through the computer 6, and this signal is sent by the digital output port of the data acquisition circuit 5 to control The low-pass filter 4 completes the control of different cut-off frequencies to meet more detection needs.

The data acquisition circuit 5 is a data acquisition module based on the PCI bus, which is directly plugged into the PCI bus interface of the computer 6 to realize the field data acquisition to the computer 6 and output the control data of the computer 6 to the front-end controlled through the data acquisition circuit 5 object.

In a preferred embodiment, the data acquisition circuit 5 adopts the DAQ-2010 multifunctional 4-channel synchronous data acquisition card of ADLINK Company, which has 14-bit A/D resolution and the highest sampling frequency can reach 2MHz. According to the national standard of power grid quality, the frequency measurement range of A-level instruments is 0-2500Hz, that is, the highest harmonic of the sampling signal is 50 times. According to the Nyquist sampling theorem, the highest sampling frequency of the data acquisition circuit 5 can be greater than 5kHz. Therefore, DAQ-2010 can fully meet the requirements of three-phase voltage and current power quality A-level detection.

After the computer 6 acquires the voltage and current of the A phase, B phase and C phase of the power system from the data acquisition circuit 5, it calculates the effective value of the voltage and current of each phase, and calculates the effective value of the voltage and current of each phase based on the effective value of the voltage and current of each phase Active power, apparent power, power factor, etc.

According to the circuit theory, for the voltage signal u(t) and current signal i(t) changing with time, the effective values of phase voltage, phase current and active power are defined as:

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}\underset{\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; T</span>}}{<span\; class="notranslate">\; \&Integral;</span>}}\mathrm{<span\; class="notranslate">\; u</span>}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; dt</span>}}$ ${\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}\underset{\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; T</span>}}{<span\; class="notranslate">\; \&Integral;</span>}}\mathrm{<span\; class="notranslate">\; i</span>}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; dt</span>}}$ ${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}\underset{\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; T</span>}}{<span\; class="notranslate">\; \&Integral;</span>}}\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; dt</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

The measured AC signal is sampled N times in one cycle, u _k and _ik are the instantaneous values of voltage and current sampling at the kth time interval, and ΔT _k is the time interval between two adjacent sampling times, then the phase voltage, The effective values of current and single-phase active power are:

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}\underset{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="k"\; filenames="HSA00000840388200021.png"\; state="\{\{state\}\}">k</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}}$ ${\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}\underset{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="i\; k"\; filenames="HSA00000840388200021.png"\; state="\{\{state\}\}">i</figure-callout></span><figure-callout\; id="2"\; label="i\; k"\; filenames="HSA00000840388200021.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}^{\mathrm{<span\; class="notranslate">k</span>}}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}}$ ${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}\underset{\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

则：The frequency tracking technology is used in sampling, so that the number of sampling points in one cycle is N, and the time interval between two adjacent samples is equal, and ΔT _k is the time constant ΔT,

but:

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}}\underset{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}$ ${\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}}\underset{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}$ ${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}}\stackrel{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\underset{\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

The single-phase power factor is:

The total active power of the three phases is: $P=\frac{1}{N}(\underset{k=0}{\overset{N-1}{\mathrm{\&Sigma;}}}{u}_{\mathrm{ak}}{I}_{\mathrm{ak}}+\underset{k=0}{\overset{N-1}{\mathrm{\&Sigma;}}}{u}_{\mathrm{bk}}{I}_{\mathrm{bk}}+\underset{k=0}{\overset{N-1}{\mathrm{\&Sigma;}}}{u}_{\mathrm{ck}}{I}_{\mathrm{ck}})$

The total apparent power of the three phases is: S＝U _A I _A +U _B I _B +U _C I _C

The three-phase total power factor is:

Although the sampling frequency of the power system cannot be determined in advance, the inertia of the power system is large, and the frequency of two or several adjacent cycles changes very little, so the previous (or several) cycles adjacent to the cycle to be sampled can be used The frequency of the frequency is used to replace the fundamental frequency of the cycle being sampled to determine the frequency of the sampled signal.

When the three-phase electricity does not contain zero-sequence components such as three-phase line voltage and three-phase line current without a neutral line, the national standard gives an accurate calculation formula for the three-phase unbalance:

${\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 6</span>}\mathrm{<span\; class="notranslate">\; L</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 6</span>}\mathrm{<span\; class="notranslate">\; L</span>}}}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}<span\; class="notranslate">\; \%</span><span\; class="notranslate">\; ,</span>$ $\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; A</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="4"\; label="B"\; filenames="HSA00000840388200021.png"\; state="\{\{state\}\}">B</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; C</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}}{{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; A</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="B"\; filenames="HSA00000840388200021.png"\; state="\{\{state\}\}">B</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; C</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

Among them, A, B, C are the amplitudes of the three-phase line voltage (current), such as: U _ab , U _bc , U _ca or I _a , I _b , I _c

The phase difference is obtained by using the principle that the value of the cross-correlation function when the time delay z=0 of two sinusoidal signals of the same frequency is proportional to the cosine value of the phase difference. Since the noise signal usually has little correlation with the effective signal, this method has good noise suppression ability.

Usually, the measurement of voltage fluctuation adopts the following method: measure the effective value of each cycle (20ms) within a fixed time, and then compare the above effective values, and divide the maximum difference ΔU(U _max -U _min ) by the nominal voltage The percentage of U _N (rated voltage U _N ) represents its relative percentage value, that is, the magnitude of the voltage fluctuation rate d, that is, the voltage fluctuation rate:

$\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&Delta;\; U</span>}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}<span\; class="notranslate">\; \%</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; max</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; min</span>}}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}<span\; class="notranslate">\; \%</span>$

From the above analysis, it can be seen that after the computer 6 obtains the voltage and current of the A phase, B phase and C phase of the power system from the data acquisition circuit 5, the effective value of the voltage of each phase, the effective value of each current, and the effective value of each phase can be obtained by calculation. Power parameters such as power, apparent power, power factor, grid frequency, three-phase unbalance and phase difference. Therefore, the detection system proposed in this application can better complete the measurement of basic power parameters and realize power quality detection according to GB.

Claims (5)

1. a parameters of electric power detection system is characterized in that, comprising: the sensor assembly that connects electric system; Be connected to analog switching circuit, amplifying circuit and the low-pass filter circuit of described sensor assembly output terminal in turn; Be used for gathering the data acquisition circuit of each phase voltage of electric system, current data, described data acquisition circuit is connected the output terminal of described low-pass filter circuit; Be used for calculating according to each phase voltage, current data the computing machine of every parameters of electric power of electric system, described computing machine connects described data acquisition circuit.

2. according to the described parameters of electric power detection system of claim 1, it is characterized in that described sensor assembly comprises voltage transformer (VT) and the current transformer that connects electric system respectively.

3. according to the described parameters of electric power detection system of claim 1, it is characterized in that described analog switching circuit is the analog multiplexer of 16 passages/pair 8 passages, four control ports of described analog multiplexer connect described data acquisition circuit.

4. according to the described parameters of electric power detection system of claim 1, it is characterized in that described low-pass filter circuit is the fertile low-pass filter now of the program-controlled quadravalence Bart of cutoff frequency.

5. according to claim 1 or 2 or 3 or 4 described parameters of electric power detection systems, it is characterized in that described data acquisition circuit connects described computing machine by pci bus interface.

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