CN104345218B - Three-phase reactor reactance value measuring system and method - Google Patents

Abstract

A reactance value measuring system for three-phase reactor, comprising: the dc source that the DC side of three phase inverter unit provides for inverter through rectification or with battery for system, the output of AC connect respectively tested three-phase reactor one end after the low pass filter of RC composition; Tested three-phase reactor other end welding system neutral point; Three-phase electricity detecting signal unit is connected on respectively that three phase inverter unit exports in the triple line that connects tested three-phase reactor, the current signal of its collection exports respectively the first binding post of calculation control unit to; The composition of calculation control unit with annexation is: the first binding post, modulate circuit, A/D, CPLD, dual port RAM and the DSP that are connected successively, CPLD also distinguishes external PWM transmission circuit and input and output circuit, and described PWM transmission circuit and input and output circuit outreach by the second binding post. The present invention has compact conformation, function advanced person, high, the convenient on-the-spot feature using of test efficiency, and it is little to measure accurate error.

Description

Three-phase reactor reactance value measuring system and method

Technical field

The present invention relates to a kind of three-phase reactor reactance value measuring system. The invention still further relates to and adopt described system to carry out three-phase reactanceThe method that device reactance value is measured.

Background technology

Reactor is a kind of conventional, important power equipment in electrical network, is widely used in reactive-load compensation, current limliting, steady in circuitThe aspects such as stream (flat ripple), filtering, damping, phase shift. GB/T1094.6-2011 " power transformer the 6th part: reactor "List the measurement of reactor reactance value in delivery test project; To the reactor having put into operation, its reactance value measurement is to judge itThe no important indicator of normal operation, lists preventive trial project in; And according to national Specification, to iron core reactor reactance measurementShould be greater than under 90% rated current just effective.

Traditional three-phase reactor reactance value measurement mechanism, by generator, pressure regulator, compensation condenser group, current transformer,Voltage transformer, voltmeter, ammeter, stube cable and supporting securing member composition. There is take up room large, structure in such deviceThe shortcoming scattered, cost is high, can only be for the manufacture of factory or professional test mechanism; At present, to the reactor having come into operation, severalCannot complete reactance measurement.

Further, traditional three-phase reactor reactance value measurement is based on three-phase symmetric voltage source metering system, itself has following lackingFall into: (1) inductance measurement result is relevant with the internal resistance of source, and different internal resistance test result differences, therefore the systematic error of existence; (2) veryDifficulty accomplishes that the value of three-phase current is more approaching, and three-phase current varies in size affects alternate induced voltage by mutual inductance, thereby knot is measured in impactReally, about current deviation no standard; (3) even if can accomplish that three-phase electricity flow valuve equates, but three-phase current may not be symmetrical, still impactAlternate induced voltage, causes measuring inaccurate.

Summary of the invention

First technical problem to be solved by this invention, proposes a kind of three-phase reactor reactance value measuring system exactly.

Second technical problem to be solved by this invention, proposes exactly the described system of a kind of employing and carries out three-phase reactor reactance valueMeasuring method.

System of the present invention has compact conformation, function advanced person, high, the convenient on-the-spot feature using of test efficiency, and adopts instituteIt is little that the reactance value measuring method that the system of stating is carried out three-phase reactor is measured accurate error.

Solve above-mentioned first technical problem, the technical solution used in the present invention is:

A reactance value measuring system for three-phase reactor, is characterized in that: comprise three phase inverter unit, the inspection of three-phase electricity signalMeasurement unit and calculation control unit;

Dc source that the DC side of described three phase inverter unit provides for inverter through rectification or with battery for system,The output of AC connects respectively tested three-phase reactor one end after the low pass filter of RC composition; The tested three-phase reactor other endWelding system neutral point;

Described three-phase electricity detecting signal unit is connected on respectively three phase inverter unit and exports to and connect three of tested three-phase reactorIn phase line, the current signal of its collection exports respectively the first binding post of calculation control unit to;

The composition of described calculation control unit with annexation is: the first binding post of being connected successively, modulate circuit, A/D,CPLD (ComplexProgramableLogicDevice), dual port RAM and DSP (DigitalSignalProcessing), describedCPLD also distinguishes external PWM transmission circuit and input and output circuit, and described PWM transmission circuit and input and output circuit are by theTwo binding posts outreach.

The low pass filter of described RC composition is resistance and the electric capacity of series connection, the Hall voltage sensor in parallel at electric capacity two ends, itsOutput u_A、u_B、u_C。

Described three phase inverter unit adopts 3 single-phase inverter compositions, and three phase inverter unit adopts PWM (pulsewidth modulation)Technology, the frequency of PWM is at 2～12kHz, instruction cycle 40us, device sine wave output frequency range is 0.5～50Hz;

Described three-phase electricity detecting signal unit adopts Hall current sensor to measure three-phase current i_A、i_B、i_C, adopt RC filtered electricalRoad (seeing Fig. 3 modulate circuit) and Hall voltage sensor measurement three-phase voltage u_A、u_B、u_C；

Described calculation control unit CPU adopts the floating point DSP chip TMS320C6713 of TI company, and core frequency can reach225MHz. Logic chip adopts CPLD, controls 14 AD of outside 8 passage, and sends PWM instruction. Controller inside possesses oneThe switching value input/output module of determined number, for controlling external communication contactor.

Solve above-mentioned second technical problem, the technical solution used in the present invention is:

Adopt described system to carry out a method for three-phase reactor reactance value measurement, comprise the following steps:

The first step, calculates native system institute according to the volumeter of specified inductance value, rated current and the native system of tested three-phase reactorThe peak frequency that can bear;

Second step, calculates sampled voltage phase shift and the amplitude coefficient that RC wave filter causes, the anti-voltage that pushes away according to native system output frequencyZero crossing;

The 3rd step, finds voltage over zero according to detecting magnitude of voltage, and sets up sin ω t and cos ω t;

In formula, ω is power supply angular frequency; T is the time;

The 4th step, calculate gaining merit and reactive current of output current according to sin ω t and cos ω t:

$I_{M1}=\frac{2}{N}\underset{k=1}{\overset{N}{\mathrm{\Σ}}}{i}_k\sin \left(k\right);$

$I_{M2}=\frac{2}{N}\underset{k=1}{\overset{N}{\mathrm{\Σ}}}{i}_k\cos \left(k\right);$

In formula, I_M1、I_M2Be respectively watt current, peak value of idle current; N is a cycle discrete point number; i_kIt is the electric current detectingDiscrete signal; Sin (k), cos (k) are respectively the discrete magnitudes of sin ω t and cos ω t;

The 5th step, the inductance value according to voltage and reactive current calculating reactor:

$L=\frac{U_M}{\mathrm{\ω}{I}_{M2}}$

Because the capacity formula of three-phase reactor is P_N＝3ωL_NI²The capacity that is reactor is directly proportional to the frequency that applies electric current,Therefore under same test current, reduce ω and can effectively reduce capacity of experiment, also just can reduce required testing equipment capacity.

So thinking of the present invention is that the frequency by reducing to measure power supply reaches and reduces measurement device capacity problem, meets on-the-spotMeasure requirement; The current source of making three-phase controlled frequency, controlled current flow substitutes three-phase voltage source to improve the accurate of three pole reactor measurementProperty.

The present invention compared with prior art has following advantage:

1, the sine wave freuqency scope of system output of the present invention is 0.5～50Hz, and the capacity public affairs of three-phase reactorFormula is P_N＝3ωL_NI²Therefore under same test current, reduceCan effectively reduce required testing equipment capacity.

2, three phase inverter of the present invention unit adopts current tracking PWM technology, the three-phase electricity flow valuve pair of outputClaim and equate, having eliminated the adverse effect of current deviation to mutual voltage, having improved accuracy of measurement, having eliminated the shadow of the internal resistance of sourceRing, measurement result does not have Systematic Errors.

Brief description of the drawings

Fig. 1 a is one of structural representation of the present invention (wiring diagram);

Fig. 1 b is two (three-phase inverting circuits) of structural representation of the present invention;

Fig. 2 is the wiring schematic diagram of three-phase electricity detecting signal unit;

Fig. 3 is calculation control unit composition and annexation schematic diagram.

Detailed description of the invention

Below in conjunction with accompanying drawing, the invention will be further described.

Participate in 4 years Fig. 1-Fig. 3, the reactance value measuring system embodiment of three-phase reactor of the present invention, comprises three phase inverterUnit, three-phase electricity detecting signal unit and calculation control unit.

Dc source that three phase inverter unit DC side provides for inverter through rectification or with battery for system, ACOutput connects respectively tested three-phase reactor one end after the low pass filter (A, the B of Fig. 1 a, the external connecting circuit of C) of RC composition,Tested three-phase reactor other end welding system neutral point; Three-phase electricity detecting signal unit is connected on respectively the output of three phase inverter unitTo connecing in the triple line of tested three-phase reactor, the current signal of its collection exports respectively the first terminals of calculation control unit toSon; Calculating the single composition of control with annexation is: the first binding post, modulate circuit, A/D, the CPLD, two that are connected successivelyMouthful RAM and DSP, CPLD also distinguishes external PWM transmission circuit and input and output circuit, described PWM transmission circuit and opening into openingGoing out circuit outreaches by the second binding post.

Three phase inverter unit adopts 3 single-phase inverter compositions, and three phase inverter unit adopts PWM (pulsewidth modulation) skillArt, the frequency of PWM is at 2～12kHz, instruction cycle 40us, device sine wave output frequency range is 0.5～50Hz; Three-phase telecommunicationsNumber detecting unit adopts Hall current sensor to measure three-phase current i_A、i_B、i_C, adopt RC filter circuit and Hall voltage sensingDevice is measured three-phase voltage u_A、u_B、u_C; Calculation control unit CPU adopts the floating point DSP chip TMS320C6713 of TI company,Core frequency can reach 225MHz. Logic chip adopts CPLD, controls 14 AD of outside 8 passage, and sends PWM instruction.Controller inside possesses the switching value input/output module of some, for controlling external communication contactor.

The current signal of Hall current sensor collection enters A/D converter through the RC of control panel filtering, and CPLD controls AD samplingTime, the signal of collection is write to dual port RAM; DSP establishes according to tested three-phase reactor rated current, specified inductance value and testStandby volumeter calculates amplitude and the frequency of instruction current, writes back CPLD through dual port RAM, and CPLD adopts stagnant ring comparative approach to produceRequired pwm signal, delivers to driver through isolating chip; Between controller and inverter, adopt optical-fibre communications, improve testing equipmentThe interference free performance of calculation and control device unit.

The method that adopts said system to carry out the measurement of three-phase reactor reactance value, comprises the following steps:

The first step, calculates native system institute according to the volumeter of specified inductance value, rated current and the native system of tested three-phase reactorThe peak frequency that can bear;

Second step, calculates sampled voltage phase shift and the amplitude coefficient that RC wave filter causes, the anti-voltage that pushes away according to native system output frequencyZero crossing;

The 3rd step, finds voltage over zero according to detectable voltage signals, and sets up sin ω t and cos ω t;

The 4th step, calculates gaining merit and reactive current of output current according to sin ω t and cos ω t;

The 5th step, according to the inductance value of voltage and reactive current calculating reactor.

Claims (3)

1. a reactance value measuring system for three-phase reactor, is characterized in that: comprise three phase inverter unit, three-phase electricity detecting signal unit and calculation control unit;

The dc source that the DC side of described three phase inverter unit provides for inverter through rectification or with battery for system, the output of AC connect respectively tested three-phase reactor one end after the low pass filter of RC composition; Tested three-phase reactor other end welding system neutral point;

Described three-phase electricity detecting signal unit is connected on respectively that three phase inverter unit exports in the triple line that connects tested three-phase reactor, the current signal of its collection exports respectively the first binding post of calculation control unit to;

The composition of described calculation control unit with annexation is: the first binding post, modulate circuit, A/D, CPLD (ComplexProgramableLogicDevice), dual port RAM and the DSP (DigitalSignalProcessing) that are connected successively, described CPLD also distinguishes external PWM transmission circuit and input and output circuit, and described PWM transmission circuit and input and output circuit outreach by the second binding post.

2. the reactance value measuring system of three-phase reactor according to claim 1, is characterized in that: the low pass filter of described RC composition is resistance and the electric capacity of series connection, the Hall voltage sensor in parallel at electric capacity two ends, and it exports u_A、u_B、u_C。

3. the method that the system of employing as described in claim 1-2 any one carried out the measurement of three-phase reactor reactance value, is characterized in that comprising the following steps:

The first step, calculates according to the volumeter of specified inductance value, rated current and the native system of tested three-phase reactor the peak frequency that native system can bear;

Second step, calculates sampled voltage phase shift and the amplitude coefficient that RC wave filter causes, the anti-voltage over zero that pushes away according to native system output frequency;

The 3rd step, finds voltage over zero according to detecting magnitude of voltage, and sets up sin ω t and cos ω t;

In formula, ω is power supply angular frequency; T is the time;

The 4th step, calculate gaining merit and reactive current of output current according to sin ω t and cos ω t:

In formula, I_M1、I_M2Be respectively watt current, peak value of idle current; N is a cycle discrete point number; i_kIt is the electric current discrete signal detecting; Sin (k), cos (k) are respectively the discrete magnitudes of sin ω t and cos ω t;

The 5th step, the inductance value according to voltage and reactive current calculating reactor:

Because the capacity formula of three-phase reactor is P_N＝3ωL_NI²The capacity that is reactor is directly proportional to the frequency that applies electric current, therefore, under same test current, reduces ω and can effectively reduce capacity of experiment, also just can reduce required testing equipment capacity.