Harmonic distortion

High skew rate Intermodulation distortion Harmonic distortion Phase distortion Crossover distortion... 

In his classical paper, Renner [7] first explained the physical background of the vibronic coupling in triatomic molecules. He concluded that the splitting of the bending potential curves at small distortions of linearity has to depend on p, being thus mostly pronounced in H electronic state. Renner developed the system of two coupled Schrbdinger equations and solved it for H states in the harmonic approximation by means of the perturbation theory. 

The coordinates of interest to us in the following discussion are Qx and Qy, which describe the distortion of the molecular triangle from Dy, symmetry. In the harmonic-oscillator approximation, the factor in the vibrational wave... 

The centrifugal distortion constant depends on the stifthess of the bond and it is not surprising that it can be related to the vibration wavenumber co, in the harmonic approximation (see Section 1.3.6), by... 

The inductor on the input side also suppresses the harmonics in the incoming supply, as high Lj will provide a high impedance path to higher harmonics. For suppression of harmonics, where the supply system is already substtintially distorted, tiddilional L-C... 

The above data is for a general reference. Actual harmonic distortion on the system during operation will depend upon the types of connected loads and their operating conditiotis, such as variation in its loading and fluctuations in the system voltage. 

UK engineering recommendation - G5/3 (British Electricity Council Standard). For harmonic voltage distortions in the system as in Table 23.2. 

IEEE-519 Guide for harmonic control and reactive compensation of static power converters, for harmonic-voltage distortions of general and dedicated power system, as in Table 23.3. 

Table 23.2 Premissible individual and total harmonic voltage distortions - as in G5/3, UK engineering recommendations...

The second component is caused by the different harmonic quantities present in the system when the supply voltage is non-linear or the load is nonlinear or both. This adds to the fundamental current, /,- and raises it to Since the active power component remains the same, it reduces the p.f of the system and raises the line losses. The factor /f/Zh is termed the distortion factor. In other words, it defines the purity of the sinusoidal wave shape. 

When the supply system itself contains harmonics and the voltage is already distorted now even the linear loads will respond to such voltage harmonics and draw harmonic currents against each harmonic present in the system, and generate the same order of current harmonics. 

If there are many large or small consumers that a distribution line is feeding, it is possible that the voltage of the network may be distorted beyond acceptable limits. In this case it is advisable to suppress these harmonics from the system before they damage the loads connected in the system. Preferable locations where the series inductor or the filter-circuits can be installed are ... 

A distribution network 33 kV, three-phase 50 Hz feeding an industrial belt with a number of medium-sized factories some with non-linear loads and some with static drives and some with both. It was observed that while the lines were apparently running reasonably loaded, the active power supplied was much below the capacity of the network. Accordingly, a harmonic study of the network was conducted and it was found that despite localized p.f. control by most factories, the p.f. of the network itself was well below the optimum level and the voltage was also distorted by more than was permissible. To improve this network to an acceptable level, we have considered the following load conditions, as were revealed through the analysis. 

All such loads generate harmonics and cause variations in the fundamental power frequency of the supply sy.stem which leads to distortion in the sinusoidal waveform of the voltage. This distortion may affect the quality of the supply system (voltage) beyond desirable limits, A non-sinusoidal and distorted supply system may adversely affect the different loads connected on the system, besides leading to outage of the sy.stem itself. 

A term used in PFC is total harmonic distortion. This is defined as... 

Both single-phase charging systems and three-phase charging systems would contain power electronic devices that as a side effect introduce waveform distortion and create power quality problems. Filtering devices used in conjunction with residential charging systems could be used to reduce harmonics and other power quality problems, but the cost of such filtering devices is currently quite high. 

In the Hamiltonian Eq. (3.39) the first term is the harmonic lattice energy given by Eq. (3.12). It depends only on A iU, i.e., the part of the order parameter that describes the lattice distortions. On the other hand, the electron Hamiltonian Hcl depends on A(.v), which includes the changes of the hopping amplitudes due to both the lattice distortion and the disorder. The free electron part of Hel is given by Eq. (3.10), to which we also add a term Hc 1-1-1 that describes the Coulomb interne-... 

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