A New AC Voltage Regulator Using Thyristors

Analysis of voltage rise phenomenon in distribution lines associated with grid-connected renewable energy system

“…In the former case, the excessive voltage drop occurs when the power plant has stopped. And also, it is difficult to use the on-line tap changer since the grid voltage is 22.9kV [17,18]. In the latter case, it can be only possible for the synchronous generator and the continuous operation is difficult due to the requirement of the excessive leading control.…”

An Improved Control Scheme for On-load Tap Changers with Reduced Harmonics Injection

“…The above drawbacks were greatly reduced with an electronically assisted OLTC regulator topology, as shown in Figure 1(b) [21], although there are various alterations and modifications in the OLTC schemes [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] in between to eliminate the problems already mentioned. The OLTC regulator has a number of tapings on the secondary or primary of the main transformer, which are connected to load terminals through fast-acting solid-state switches.…”

“…It has considerable limitations and drawbacks, including arcing, high maintenance costs, and slow response time [1]. To address these limitations and drawbacks, new configurations for tap changers have been recommended [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20].They have been classified in to two groups: the electronically assisted OLTC regulator [2][3][4][5][6][7][8][9][10] and the fully electronic OLTC regulator [11][12][13][14][15][16][17][18][19][20][21]. Various other feasibility propositions for electronic tap-changing stabilizers have been reviewed for medium-voltage lines [4].…”

“…In the 1970s, comprehensive studies were carried out to avoid the number of tapings in the power transformer with the help of high-frequency solid-state switches along with a compensating transformer [9][10][11][12][13]. However, these techniques are limited to special applications.…”

A novel ac-ac buck-boost voltage regulator with unity input power factor

“…The conventional ac regulators that can provide good sinusoidal output voltage are: variacs adjustable mains transformers driven by motors, mains transformers with electronically controlled taps using triacs (Servetas and Vlachakis 1981), saturable reactor regulators, and regulator circuits based on ac recti® cation followed by dc-to-ac inverters. These categories of regulator have the disadvantage in that they all need to use bulky mains-frequency transformers or autotransformers.…”