The most important feature of the harmonic, alternating current is its separation from a full, smooth and clean sine wave shape. Increased harmonics from power electronics are becoming increasingly important problems in industrial plants.Harmonics in general, any one or both of the nonlinear elements and the nonsusoidal sources are present in the system. Sinusoidal waves other than basic waves are called “harmonic.. The presence of harmonic current and voltage in power systems means that the sinusoidal wave is disturbed. Distorted waves are called nonsusoidal waves in the technical literature. It is a new term that comes into use with the spread of the use of electronic devices such as harmonics, converters, transformers, generators, arc furnaces, some types of lighting, computers, printers, televisions, telephone chargers and uninterruptible power supplies. as known alternating voltage in the form of a sine wave with a certain frequency. frequency of the alternating voltage used in Turkey 50 Hz.
Harmonics for non-sinusoidal waveforms can also be measured with the energy analyzer. In addition to displaying various parameters, you can also print, store and transfer this data to other similar networks by installing the necessary spelling programs.The energy analyzer is also used for many different electrostatic analyzers. The electrostatic energy analyzer is an ion optical instrument that uses an electric field to allow the passage of ions or electrons of a given specific energy.In power systems, it is desired that the waveform of current and voltage be ideally sinusoidal. But this is not always possible. Here harmonic is the distortion of the sinusoidal waveform in A.A. Signals at different frequencies distort the structure of the pure sinusoidal waveform.Causes of sinusoidal wave distortion; switching effects of semiconductor elements and connecting nonlinear loads (transformer, arc furnaces, induction furnaces, etc.) to the network.
All consumers receiving energy from the electricity distribution system create distorting effects in relation to the short circuit power ratio of the point where the devices they use are connected. The causes of the most disturbing effects in the electricity networks and their negative effects can be explained as follows:
- Sudden changes and fluctuations in the amplitude and frequency of voltage
- Load imbalances
- Harmonics or intermediate harmonics
Among these effects, a negative situation experienced by consumers is the Fliker effect, which is perceived as fluctuation of light glare, which occurs in lighting means due to voltage fluctuation. Acceptable flicker levels according to international standards are as follows:
- 380 kVolt and over at very high stress 0,85
- 36 at high voltage from 380 kVolt to 0,97 kVolt
- Medium and low voltage 1,15
Due to the nature of the semiconductor elements and the effect of some nonlinear loads such as transformers or arc furnaces used in industry, current and voltage waveforms are periodic, but are composed of the sum of sinusoidal waves and other sinusoidal waves of different frequency and amplitude. These sinusoidal waves other than the basic wave are called harmonics. This is caused by saturation in magnetic circuits, power control elements, nonlinear loads, transformer magnetizing currents operating in the saturation zone, continuous power supplies, computers, fluorescent lamps, electronic ballasts, battery charging systems, semiconductor controlled devices and discharge lamps.The presence of harmonic current and voltage in power systems means that the sinusoidal wave is disturbed. Harmonics cause some technical and economic problems in power systems such as additional losses, resonance events, voltage drops, and change of power factor.
Distortion of voltage and current waveforms with harmonics creates many problems in energy systems. For example, generator and mains voltage deteriorates, voltage decreases, energy system elements and loads are lost, induction type meters have wrong measurements, mains resonances occur and therefore overvoltages and currents occur, protection and control systems are signal errors, insulation materials are damaged. and the life of electric vehicles is shortened.
Effects of Harmonics
Harmonics; They cause additional losses in motors, generators, capacitors, transformers and power transmission lines. In some cases, harmonics cause power system elements to be damaged or disabled. In addition, the probability of resonance event occurring due to harmonics will increase. Excessive currents and voltages that may occur as a result of resonance will cause great damage to the elements in the business.Harmonic current components created by nonlinear loads cause harmonic voltages in the system. Harmonic voltages, on the other hand, flow harmonic currents over the linear and nonlinear loads connected to this system. Thus, elements (loads) that do not generate harmonics themselves can be exposed to harmonic distortions. There are many methods to reduce the effects of existing harmonics in your system. In order to examine and eliminate these negativities of harmonic components, detailed analysis of harmonic systems is required.
These Ones;
- Reduce Harmonic Currents
- filtering
- Active Filter
- Passive Filter
- Mixed Filter
- Circuit Breakers
Total Harmonic Voltage Distortion (THD) in accordance with Energy Market Regulatory Authority (EMRA) standardsV) 3%, Total Harmonic Current Distortion (THDI) Should be below 8%, if it is above, it resonates with the capacitors used in the compensation system and can damage both the capacitors and other loads in your system.As Shunttech, we provide "Harmonic Analysis Measurement and Reporting" services to both state institutions and private sector organizations to detect voltage and current harmonics before they damage their systems and to offer solutions according to existing harmonic types. The "Energy Analyzer" used during the measurement has been approved by the calibration laboratories accredited by TURCERT. In addition, it is offered within the Harmonic Analysis, Measurement and Reporting service for detecting power quality disturbances such as voltage drop (right), voltage rise (swell), nominal value jumps (notch) and short-term voltage interruptions (outage).Our company conducts harmonic energy analyzes in accordance with the relevant legal regulations, standards and test methods published by domestic and foreign institutions within the framework of electrical safety inspections.
