The disturbances called harmonics are caused connecting non-linear loads, such equipment incorporating power electronics, the network. All the equipment factories and buildings now includes digital electronics which are known sensitive micro-outages, peaks and dips, harmonics and disturbances general.
Power measurements
Power measurement key element for the definition, success and longterm effects energy optimization programme. The causes mainly lie the installation itself.Power, ENERGY AND DISTURBANCE
A phase analysis essential precisely identify the behaviour the installations and determine which solutions implement. welding units motors) has taken into account when flicker sources with long variable operating cycles are involved (electric arc furnace), the resulting disturbance must assessed over longer time. This current distortion implies distortion the voltage also depending the impedance the source. They have provide direct measurements, allow much parameterization possible for recording and facilitate subsequent analysis. The voltage amplitude crucial parameter for electricity quality. Several types faults are then defined: overvoltage, voltage dip, outage, etc.. The measurements made help ensure that the solutions are pertinent and that the gains achieved are maintained over the long term the context energy optimization programme. Electricity suppliers penalize consumers whose displacement power factor (cos phi DPF) lower than 0.. measurement provides the foundation for optimizing your installations' energy efficiency, supervising your electrical networks and fairly allocating the costs. The various parameters the installation are measured regularly, including the different power values used size the electrical network and the phase shift data, well the voltage, current and frequency measurements. reality, the flicker value the result statistical calculation based measurements the rapid voltage variations. This may have instant consequences certain electronic equipment: operating problems (synchronization, switching), untimely tripping, measurement errors energy meters, etc. Reducing electricity consumption also simple, painless way saving money. the combined effect several disturbance-generating loads operating random way (e. Harmonics and interharmonics. general, most disturbances are caused by: Slow and transient voltage variations. The complexity industrial equipment makes vulnerable the voltage disturbances that occur the electrical network. Flicker: rapid voltage fluctuations. The rated network voltage variation range set the power distributor. The quality requirements have become much more demanding and stringent than the past.g. For private customers, reactive power neither measured nor billed separately. Electricity clean energy source and less harmful for the environment, but does affect nevertheless. the medium term, the extra heating caused this may reduce the life span rotating machines, capacitors, power transformers and neutral conductors. further complication the fact that electricity market deregulation could lead increase the frequency general network blackouts. Instead included flat rate the active power price.). The voltage amplitude varies abnormally and may even drop level close zero. This phenomenon called flicker. This set measurements will help the installation manager size the capacitor banks correctly. When variable loads such arc furnaces, laser printers, microwave ovens air-conditioning systems are started up, they cause rapid voltage variations.93 (in France) whose tan phi higher than 0.4 (in France). Today's measurement instruments have capable performing this harmonic analysis order order, well measuring the Total Harmonic Distortion (THD) for more detailed diagnosis the installation. The arrival new quick-switching components leading large number low-order harmonic currents (3, 11, .
Page 78
..
Detection disturbances
With the spread systems incorporating electronics using switching power supplies, the electrical network becoming increasingly polluted.
Electrical network analysers capable recording disturbances for industrial companies and professionals the electricity sector (producers, transmission companies, electricity users) are essential tools for satisfactory supervision and timely maintenance installations. Some faults are encountered very frequently. The waveform the current consumed loads connected the electrical network often longer purely sinusoidal. 10-minute interval considered acceptable compromise for evaluation the short-term flicker (Pst). The measurement duration defined then hours, time considered appropriate for the load operating cycle the time during which observer may sensitive long-term flicker (Plt). Things are very different for industrial customers, however. The connection heavy loads may lead voltage variations the short-circuit power point supply undersized
