A large three-phase autotransformer may have a " buried " delta winding, not connected to the outside of the tank, to absorb some harmonic currents.
12.
Lowenstein's company also sells a " zig-zag transformer " which diverts harmonic currents and dissipates them as heat into transformers that have been specially modified.
13.
Triplen harmonic currents ( odd multiples of the third harmonic ) are additive, resulting in more current in the shared neutral conductor than in any of the phase conductors.
14.
Furthermore, if we assume the voltage of the mains supply is a single frequency ( which it usually is ), this shows that harmonic currents are a bad thing.
15.
Any load mismatch behind the filter can only act on the first harmonic current waveform, clearly only a purely resistive load makes sense, then the lower the resistance, the higher the current.
16.
By connecting the TCR in delta, the harmonic currents of order 3n ( " Triplen harmonics " ) flow only around the delta and do not escape into the connected AC system.
17.
Here, the harmonic currents feed on each other, multiplying so that they can exceed the capacity of that neutral conductor long before the actual power capacity of the entire system is tapped out.
18.
The TSC is usually tuned to a non-integer harmonic of the mains frequency so as to avoid the risk of the TSC being overloaded by harmonic currents flowing into it from the AC system.
19.
This presents a particular problem for the power companies, because they cannot compensate for the harmonic current by adding simple capacitors or inductors, as they could for the reactive power drawn by a linear load.
20.
These devices draw electricity in an abrupt pulse from the peaks of the electrical wave's curves, causing distortion of the wave pattern which results in harmonic currents flowing back into other areas of the power system.
