CN205193159U - Dry -type air -core reactor loss detection device - Google Patents

Abstract

The utility model discloses a dry -type air -core reactor loss detection device, including the RC divider, get the electric coil, a current transformer, a sampling circui, computing circuit and wireless transmission circuit, a sampling circui, the computing circuit, the wireless transmission circuit connects gradually, the RC divider, current transformer with get the electric coil and will hold voltage signal through the wire respectively, phase electric current signal and power transmission are to sampling circuit, sampling circuit received signal handles the back, again with signal transfer to computing circuit, the computing circuit calculates the fundamental wave loss that obtains dry -type air -core reactor, and send fundamental wave loss information to the receiving circuit of outside through the wireless transmission circuit, so that it shows or informs the host computer through the net twine to send the display to by receiving circuit. The utility model discloses the harmonic that can eliminate the variance component causes the nondeterminacy to reactor loss measurement, has avoided the harmonic of power and the nondeterminacy that the frequency fluctuation leads to reactor loss measurement, has guaranteed loss measurement's exactness.

Description

A kind of dry-type air-core reactor loss pick-up unit

Technical field

The utility model relates to reactor detection technique, particularly relates to a kind of dry-type air-core reactor loss pick-up unit.

Background technology

Reactor, as the important component part of electric system, is improving power supply quality important role.Existing reactor loss detection method adopts the consume of reactor loss measurement equipment to reactor to measure, in reactor industry, internationally recognized reactor loss measurement equipment is the 9901A electric bridge that phoenix company of the U.S. produces, but it has the following disadvantages when detecting:

(1) the loss of reactor accounts for 3 ‰ ~ 2% of its rated capacity usually, and require to reach specified to the range of voltage, electric current, voltage and current value directly reads from instrument, because meter reading exists error, and loss generally belongs in instrument measurement error range, the correctness of loss measurement therefore can be affected.

(2) the loss of reactor is relevant with applied voltage, when power supply exists voltage dithering, correctly cannot read magnitude of voltage instrument, and square being directly proportional of loss and voltage, voltage error is larger, and the error of gained loss is larger.

(3) the harmonic wave of power supply and frequency jitter all can cause the uncertainty of reactor loss measurement, thus affect the Measurement accuracy of loss.

Adopt existing reactor loss detection method to measure reactor loss, because reactor power factor is too low, it is too small that loss accounts for capacity ratio, and existing reactor loss measurement equipment does not have enough precision, therefore cannot meet reactor consume and measure requirement.

Utility model content

The purpose of this utility model is to provide a kind of easy to use, dry-type air-core reactor loss pick-up unit that accuracy of detection is high.

The purpose of this utility model realizes by the following technical solutions: a kind of dry-type air-core reactor loss pick-up unit, it is characterized in that: it comprises the RC divider of collection terminal voltage signal in the carrier for being arranged on dry-type air-core reactor, for the electricity taking coil of powering, for gathering the current transformer of phase current signal, sample circuit, counting circuit and wireless transmission circuit, described sample circuit, counting circuit, wireless transmission circuit connects successively, described RC divider, current transformer and electricity taking coil respectively by wire by terminal voltage signal, phase current signal and electric power transfer are to sample circuit, after described sample circuit Received signal strength processes, transmit signals to counting circuit again, described counting circuit calculates the first-harmonic loss of dry-type air-core reactor, and first-harmonic loss information is sent to outside receiving circuit by wireless transmission circuit, to send display to by receiving circuit show or circulate a notice of host computer through netting twine.

The harmonic wave that the utility model can eliminate heterogeneity causes the uncertainty to reactor loss measurement, avoid the uncertainty that the harmonic wave of power supply and frequency jitter cause reactor loss measurement, it also avoid the defect that loss belongs within the scope of existing instrument reading error and power supply exists voltage dithering and causes loss measurement is inaccurate simultaneously, thus ensure that the correctness of loss measurement.

Receiving circuit of the present utility model can receive the loss of reactor, temperature, running state information (whether there is turn-to-turn short circuit, broken string), also can receive the health information of reactor.

Sample circuit described in the utility model adopts A/D chip MAX1324, described counting circuit adopts DSP28335 chip, A/D chip MAX1324 receive reactor A, B, C tri-phase acquisition terminal voltage signal and phase current signal, after A/D chip MAX1324 analog to digital conversion, digital signal after conversion is transported to DSP28335 chip process, calculates the first-harmonic loss of dry-type air-core reactor.

Compared with prior art, the utility model has following significant effect:

The harmonic wave that the utility model can eliminate heterogeneity causes the uncertainty to reactor loss measurement, avoid the uncertainty that the harmonic wave of power supply and frequency jitter cause reactor loss measurement, it also avoid the defect that loss belongs within the scope of existing instrument reading error and power supply exists voltage dithering and causes loss measurement is inaccurate simultaneously, thus ensure that the correctness of loss measurement.

Accompanying drawing explanation

Below in conjunction with the drawings and specific embodiments, the utility model is described in further detail.

Fig. 1 is the schematic diagram that the utility model is arranged on reactor;

Fig. 2 is the utility model reactor loss measurement Method And Principle figure;

Fig. 3 is the composition structure and working principle block diagram of the utility model pick-up unit.

Embodiment

A kind of dry-type air-core reactor loss of the utility model detection method, comprises the following steps:

First step, gathers terminal voltage and the phase current of A, B, C three-phase of dry-type air-core reactor respectively;

Second step, in order to the harmonic wave eliminating heterogeneity causes the uncertainty to reactor loss measurement, adopts fourier algorithm to extract voltage, current first harmonics, thus calculates first-harmonic loss.

For dry-type air-core reactor wherein, if terminal voltage is u (t), phase current is i (t), due in the voltage that actual samples is come containing each harmonic, then u (t), i (t) expression formula is:

formula (1)

$i\left(t\right)=\underset{k=1}{\overset{n}{\mathrm{\Σ}}}{I}_k\sin (\mathrm{k\ωt}+{\mathrm{\φ}}_k)=I_1\sin (\mathrm{\ωt}+{\mathrm{\φ}}_1)+i_h$ Formula (2)

In formula, k represents kth subharmonic, and ω is terminal voltage first-harmonic angular frequency, and t is the time, and u (t) is terminal voltage, U _kfor kth subharmonic voltage amplitude, for kth subharmonic voltage phase angle, U ₁for the amplitude of fundamental voltage, u _hfor all the other harmonic voltage summations, i (t) is phase current, I _kfor kth subharmonic current amplitude, for kth subharmonic current phase angle, I ₁for the amplitude of first-harmonic phase current, i _hfor all the other harmonic current summations;

Third step, adopts fourier algorithm definition intermediate variable A and B:

formula (3)

formula (4)

In formula, T is terminal voltage base wave period, and ω is the angular frequency of terminal voltage first-harmonic, and n representative carries out n point equal interval sampling to u (t) between 0 to T, u (k) be kth put adopt must the magnitude of voltage of u (t), for the phase place of terminal voltage first-harmonic, U ₁for the amplitude of terminal voltage first-harmonic;

(3) the expression formula of dry-type air-core reactor first-harmonic terminal voltage, is (4) obtained by formula:

formula (5)

formula (6)

4th step, employing fourier algorithm definition intermediate variable C and D:

$C=\frac{1}{T}{\∫}_0^{T}i\left(t\right)\·\sin \mathrm{\ωtdt}=\frac{1}{n}\underset{k=0}{\overset{n}{\mathrm{\Σ}}}i\left(k\right)\·\sin \left(\frac{2\mathrm{\πk}}{n}\right)=\frac{1}{2}{I}_1\cos {\mathrm{\φ}}_1$ Formula (7)

$D=\frac{1}{T}{\∫}_0^{T}i\left(t\right)\·\cos \mathrm{\ωtdt}=\frac{1}{n}\underset{k=0}{\overset{n}{\mathrm{\Σ}}}i\left(k\right)\·\cos \left(\frac{2\mathrm{\πk}}{n}\right)=\frac{1}{2}{I}_1\sin {\mathrm{\φ}}_1$ Formula (8)

In formula, φ ₁for the phase place of phase current first-harmonic, I ₁for the amplitude of phase current first-harmonic;

(7) the expression formula of dry-type air-core reactor first-harmonic phase current, is (8) obtained by formula:

I ₁cos φ ₁=2C formula (9)

I ₁sin φ ₁=2D formula (10)

5th step, first-harmonic terminal voltage and the first-harmonic phase current of dry-type air-core reactor are respectively:

$U_1=\sqrt{4A^2+4B^2}$ Formula (11)

$I_1=\sqrt{4C^2+4D^2}$ Formula (12)

Phase differential between the first-harmonic terminal voltage of dry-type air-core reactor and first-harmonic phase current is:

formula (13)

Calculate the first-harmonic loss P of this phase of dry-type air-core reactor _haveformula be:

formula (14)

P ^have=2 (AC+BD) formula (15)

6th step, by formula (11), (12) and (13) substitute into formula (14) in, obtain formula (15), by third and fourth step calculate obtain A, B, C and D substitute into formula (15), the first-harmonic loss of this phase of dry-type air-core reactor can be obtained.

By formula (11) ~ (14) can calculate the first-harmonic terminal voltage of reactor, first-harmonic phase current and first-harmonic loss respectively, thus remove harmonic wave to the impact of first-harmonic loss measurement.The sampling number of a primitive period obtains by Zero-cross comparator, because standard first-harmonic presets according to sampled point, and survey sine and the cosine that ripple finally all will be grouped into standard, sine and cosine sum after end zero crossing can between adjacent two sampled points optional position, therefore not affect by sampled point.

When mains frequency exists fluctuation, there is the primitive period may not be sampled the cycle and divide exactly, the shake of 1 sampled point can be there is.Because voltage signal, current signal all sum up in the point that unified primitive period sampling number, thus both can produce error in the same way when being grouped into standard wave, its error is similar to (1/n) of result of calculation ², simulation result shows that this error is less than 0.1%.

As shown in Figures 1 to 3, it is the pick-up unit using above-mentioned reactor loss detection method, it comprises the RC divider 5 of collection terminal voltage signal in the carrier 4 for being arranged on dry-type air-core reactor 2, for the electricity taking coil 1 of powering, for gathering the current transformer of phase current signal, sample circuit, counting circuit and wireless transmission circuit, sample circuit, counting circuit, wireless transmission circuit connects successively, RC divider 5, current transformer and electricity taking coil 1 respectively by wire 3 by terminal voltage signal, phase current signal and electric power transfer are to sample circuit, after sample circuit Received signal strength processes, transmit signals to counting circuit again, counting circuit calculates the first-harmonic loss of dry-type air-core reactor, and first-harmonic loss information is sent to outside receiving circuit by wireless transmission circuit, to send display to by receiving circuit show or circulate a notice of host computer through netting twine.

Dry-type air-core reactor loss measurement principle as shown in Figure 2.By measuring grid side three phase terminals voltage, with the phase current of three-phase flowing through dry-type air-core reactor, then the loss of three-phase first-harmonic is:

formula (16)

In formula, U _a, U _b, U _cbe respectively three phase terminals voltage; I _a, I _b, I _cit is the phase current of three-phase; it is then the phase angle of three phase terminals voltage and phase current.

As shown in Figure 3, from dry-type air-core reactor A, B, C tri-the terminal voltage of phase acquisition after signal conditioning circuit, enter corresponding A/D chip MAX1324 with phase current signal (often having two paths of signals mutually), digital signal is converted to by A/D chip MAX1324, again the digital signal after conversion is sent in DSP28335 and processes, calculate the first-harmonic loss of dry-type air-core reactor, the result calculated the most at last shows through display circuit.Wherein, regulator rectifier circuit, crystal oscillator and reset circuit are custom circuit.

Embodiment of the present utility model is not limited thereto; according to foregoing of the present utility model; according to ordinary technical knowledge and the customary means of this area; do not departing under the utility model above-mentioned basic fundamental thought prerequisite; the utility model can also make the amendment of other various ways, replacement or change, all drops within the utility model rights protection scope.

Claims (2)

1. a dry-type air-core reactor loss pick-up unit, it is characterized in that: it comprises the RC divider of collection terminal voltage signal in the carrier for being arranged on dry-type air-core reactor, for the electricity taking coil of powering, for gathering the current transformer of phase current signal, sample circuit, counting circuit and wireless transmission circuit, described sample circuit, counting circuit, wireless transmission circuit connects successively, described RC divider, current transformer and electricity taking coil respectively by wire by terminal voltage signal, phase current signal and electric power transfer are to sample circuit, after described sample circuit Received signal strength processes, transmit signals to counting circuit again, described counting circuit calculates the first-harmonic loss of dry-type air-core reactor, and first-harmonic loss information is sent to outside receiving circuit by wireless transmission circuit, to send display to by receiving circuit show or circulate a notice of host computer through netting twine.

2. pick-up unit according to claim 1, it is characterized in that: described sample circuit adopts A/D chip MAX1324, described counting circuit adopts DSP28335 chip, A/D chip MAX1324 receive reactor A, B, C tri-phase acquisition terminal voltage signal and phase current signal, after A/D chip MAX1324 analog to digital conversion, digital signal after conversion is transported to DSP28335 chip process, calculates the first-harmonic loss of dry-type air-core reactor.