Adaptive Balancing by Reactive Compensators of Three-Phase Linear Loads Supplied by Nonsinusoidal Voltage from Four-Wire Lines
Leszek Czarnecki,
Motab Almousa
Issue:
Volume 10, Issue 3, May 2021
Pages:
32-42
Received:
13 January 2021
Accepted:
23 February 2021
Published:
20 May 2021
Abstract: A method of the design of an adaptive balancing reactive compensator in four-wire systems with linear loads and nonsinusoidal voltage is described in this article. The method of compensation is founded on the Currents’ Physical Components (CPC) – based power theory of three-phase systems with nonsinusoidal voltages and currents. The compensator is built of two sub-compensators of Y and structure, respectively. The Y compensator reduces the reactive current and the zero sequence symmetrical component of the unbalanced current. The compensator reduces the negative sequence symmetrical component of the unbalanced current. The positive sequence symmetrical component of the unbalanced current and the scattered current remain uncompensated. It is because shunt reactive compensators do not have any capability for that. Thyristor Switched Inductors (TSIs) enable the susceptance control of the compensator branches, referred to in the article as Thyristor Controlled Susceptance (TCS) branches. Periodic switching of thyristors in these branches causes the generation of harmonic currents, in particular the third-order harmonic. Moreover, in the presence of the supply voltage harmonics, a resonance of the equivalent capacitance of the compensator with the distribution system inductance can occur. These two harmful phenomena in the compensator suggested were reduced by the selection of a special structure of the TCS branches and their LC parameters. The presented method of the adaptive compensator synthesis was verified in the article with a numerical example and results of computer modeling of the load with an adaptive compensator.
Abstract: A method of the design of an adaptive balancing reactive compensator in four-wire systems with linear loads and nonsinusoidal voltage is described in this article. The method of compensation is founded on the Currents’ Physical Components (CPC) – based power theory of three-phase systems with nonsinusoidal voltages and currents. The compensator is ...
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Improving Frequency Stability of the Nigerian 330kv Transmission Network Using Fuzzy Controller
Ngang Bassey Ngang,
Bakare Kazeem
Issue:
Volume 10, Issue 3, May 2021
Pages:
43-50
Received:
3 May 2021
Accepted:
20 May 2021
Published:
27 May 2021
Abstract: The frequency instability observed in the power transmission network was mainly as a result of the per unit volts not falling within 0.95 through 1.05 P.U, volts. This has caused constant power failure in our transmission net work. This sad situation of power failure noticed in the power transmission network is contained by introducing an improvement in frequency stability of the Nigerian 330kV transmission network using fuzzy controller. It was achieved by first characterizing the 330kv transmission network by running load flow on the network, designing conventional SIMULINK model for improving frequency stability of the Nigerian 330kv transmission network, designing a rule base that makes these faulty buses to attain stability, integrating the designed rule to the conventional SIMULINK model for improving frequency stability of the Nigerian 330kv transmission network. The results obtained are conventional bus 1 per unit volts at 4s through 10s is 0.94. On the other hand, when fuzzy controller is incorporated in the system it is 1.043P.U volts. This shows that there is frequency stability when fuzzy controller is incorporated in the system since the per unit volts fall within the range of 0.95 through 1.05 P.U. volt and conventional per unit volts is 0.944 which makes the frequency unstable since the volts does not attain stability. Meanwhile, when fuzzy controller is incorporated in the system the per unit volts is 1.047. With these results, it shows that there is frequency stability when fuzzy controller is imbibed in the system. Since the per unit volt fall within the stability range of 0.95 through 1.05P.U. Volts.
Abstract: The frequency instability observed in the power transmission network was mainly as a result of the per unit volts not falling within 0.95 through 1.05 P.U, volts. This has caused constant power failure in our transmission net work. This sad situation of power failure noticed in the power transmission network is contained by introducing an improveme...
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