Electric power harmonic measures medium application and progress in wattmeter

The generation of harmonic of 1 electric power produces harmonic phenomenon to be able to undertake discussion from a few kinds of elements: Above all, the power supply with better quality appears the odds of this circumstance is smaller, the physical premise that if want,eliminates harmonic appearance is core position and span completely perfect on geometry. Actually this is impossible to happen, generate electricity additionally the process is not complete vacuum, exist impossibly also without negative factor, much better machine can exist harmonic, just measure larger little problem. As a whole the harmonic of this part does not calculate too much. Next, transformation equipment also is one of places that harmonic produces to. The core in equipment crosses n to reach upper limit, and voltaic course is not flowing. To saving the consideration of expense, so the working magnetism of transformation equipment is to be in saturation directly locally, through the electric current of magnetic field because this won't be smooth even, the saturated degree of core and the rate that harmonic produces involve into positive, this has certain law, it is the strength that degree of saturation causes the change that the job orders to cause harmonic then, former stronger, latter is caused stronger also. Again, the equipment that use phone causes harmonic, because crystal brake is in charge of rectification equipment to cause,the generation of this kind of harmonic basically is. Because crystal brake canal is in electric power engine, aluminous electrobath, charge the respect such as equipment, switchgear has wide application, generation made the harmonic that this gives electric power the network concealment in great quantities fountainhead. If rectification device is circuit of single-phase electric current, when receiving perceptual load, can contain strange second harmonic electric current, and the 3rd the content of harmonic is to be as high as more base 30% of wave; Harmonic voltage can appear when the sex that receive a facial expression is laden, among them harmonic content increases as the addition of capacitance. Calculate actually, 40% what the harmonic of because of rectification device generation occupies electric power harmonic, it is the biggest harmonic source. 1.

The measurement of 2 harmonic should study harmonic is about to be measured to undertaking, cannot want a place evasively at this moment when studying harmonic issue, also be the base that controls harmonic. Pass the measurement to harmonic, can undertake to the harmonic in power network real time detect and control, to its content and direction undertake control, analyse the flow direction of harmonic with this, have electricity of content of each n of metric positive and negative, harmonic, voltage to its amplitude, phasic wait for main parameter, for the harmonic of power network processing and control provide a basis. Because harmonic itself has not nonlinear, random sex, stable, contributing factor complex wait for character, very inaccessible to the measurement of harmonic accurate without by accident. At present the measurement of electric power harmonic means has: Imitate belt is connected or take block filter to measure, Fourier commutation is measured, instantaneous is not had result measure, nerve network is measured, small wave law is measured etc. These methods have his to have dot and drawback, use at present most extensive is Fourier alternates frequency domain analysis measures a way. The influence 　 with 2 metric to electric power harmonic 2.

The affects inductance style ammeter work of ammeter of 1 pair of inductance basically is to rely on magnetic induction to produce the moment of force that urges parts of an apparatus to turn, finish thereby metric. The magnetic flux of the electricity that place of coil of the voltage in the job produces distributes a share, cross aluminium first dish and form working magnetic flux through answering magnetism board, a side is not to cross aluminium dish the iron yoke that controls however forms minute of job magnetic flux. And the magnetism general rule that voltaic coil place produces can cross aluminium twice dish, adopt voltaic package and form loop. What arise because of voltage coil and voltaic coil is to hand in change magnetic flux, aluminium is crossed in different position dish, this is in aluminous dish on different positional generation is faradic, this kind of electric current and interaction of magnetic field generation drove aluminium dish rotational, aluminous dish of roll and power of laden have rendered great service are direct ratio relation. The ammeter design of electromagnetism induction type is with base wave to design a foundation, the tension that because of harmonic place of He Jibo overlay produces and electric current are condition of a kind of distortion, its can bring about the curve of error rate character of inductance type ammeter to appear to drop quickly, because this is in coulombmeter quantity,can be opposite the influence with the accuracy larger generation of ammeter. 2.

The photograph of the influence of ammeter of type of 2 pairs of electrons and inductive type ammeter is compared, the ammeter of electronic type is metric the error has led change to be reduced somewhat relative to Yu Pin. And with base wave is metric when be a standard, the error that the error with electronic type metric ammeter wants to compare inductive type ammeter is big still, the principle that makes because of its at this moment will decide, ammeter undertakes adoption means is: A/D is used -- multiplier -- processor -- indication output, facility has the job below the circumstance that does not exceed national level according to sine 50Hz. According to the calibrating regulation of electronic type ammeter, the lack fidelity sine wave that place of the electric current of electronic type ammeter, voltage allows is inside certain limits, and for many times harmonic will bring about whole weaveform to exceed metricly be restricted, generation is lack fidelity cause multiplier error. 3 harmonic are in metric medium application and development 　 3.

When 1 harmonic has harmonic to metric application, can cause 3 kinds of change of electric energy instrument, the first, can raise the accuracy that ammeter works, react value and real value match namely, look so, the effect that the functional addition that can be informed harmonic He Jibo rises can be regarded as a kind of metric method; The 2nd, outstanding base the action of wave and the action that weakens harmonic to be able to arise, do it from ammeter function, alter the ability of its resistance harmonic. The 3rd, use harmonic and base a certain number of property of wave are different will distinguish accept, this kind of method can apply at harmonic alone measure, as the development of time, between it and real money change a method to will have new development. 3.

The development with 2 metric harmonic sees the word of metric means of home only, what basically applying still is the method of full capabilities. The limits with this kind of metric applicable method is only base when wave is smooth, the effect inside this limits can get admissive. But influence of resistless the least bit harmonic. Once not be in this suitable scope metric data will no longer effective. Realize two-way wave part metric it is ammeter function more powerful, the performance with more excellent efficiency, because the model of two kinds of wave is different, after passing different processing, be accepted respectively and metric it is possible, and metric main goal is to harmonic, because of the interference action of harmonic, the measurement to it can counteract the generation of the error, get valid final data. 3.

The evolution of 3 harmonic ammeter had appeared to fight sexual equipment appearance about what harmonic disturbs actually, can specific application is in the place that has harmonic, nevertheless, because collect fees,criterion had be notted unite rise, without certain price, accordingly still cannot big range is used, but the inspiration that the performance dominant position that this does not affect this appearance brings people, its defying harmonic sense is tremendous. Its functional system moves by the machine in possible implementation now, spare parts invalidation, spend the state of metric data invalidation that is destroyed to cause evenly for 0. Origin of this kind of ammeter is electric energy watch, be machined through more careful technology and get. Use high capacity chip, font of Chinese character lattice, A/D combines DSP to combine the form of CPU, perfect independent computation and metric special chip ceaselessly, extended the ammeter that a large number of Cheng, wide quantity is restricted thereby, realized pair of harmonic He Jibo from this undertake parting metrical and differentiate metric capability, such ammeter were had metric base electric energy of wave have rendered great service, base wave without use up electric energy, total electric energy result electric energy, actually to wait. Brand-new improvement electronic type ammeter has more wide frequency to answer, error frequency is characteristic curvilinear general more flat, in the environment that exists to having harmonic so, although new-style ammeter has the presence of the error, compared with former inductive type instrument for, also be quite faint. And in two kinds of wave divisional measure on the effect is very good. The presence of epilogue harmonic is having negative effect at first actually. But, it advanced ammeter from opposite point of view metric career is sided with more comprehensive more advanced way develops, caused new technical discovery, this perhaps is the meaning place that harmonic exists, current, because the amount of harmonic and energy make diligent rate and the amount of the person that use are increasing, the resistance that the voltaic distortion place that arises from this has also is rising, this also advanced ammeter to study the career faces the period that needs choice more, had updated demand by force to the function with the equipment with high precision. To the processing of harmonic craft accords with old development way, each unit personnel ought to cooperate actively, find more complete processing technique and will collect fees fall to real point, find the ammeter weights and measures technique that fits our country national condition. CNC Milling