Mitigation of voltage sags, imbalances and harmonics in sensitive industrial loads by means of a series power line conditioner

• Published in: Electric power systems research Vol. 84; no. 1; pp. 20 - 30
• Main Authors: Fernandez-Comesana, Pablo, Freijedo, Francisco D., Doval-Gandoy, Jesus, Lopez, Oscar, Yepes, Alejandro G., Malvar, Jano
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2012; Elsevier
• Subjects: Active power filters; Applied sciences; Dynamic voltage restorer; Electrical engineering. Electrical power engineering; Electrical machines; Electrical power engineering; Exact sciences and technology; Miscellaneous; Operation. Load control. Reliability; Power electronics, power supplies; Power networks and lines; Regulation and control; Sags; Active power filters; Sags; Dynamic voltage restorer; Waveform; Harmonic; Electric energy transportation; Unbalanced conditions; Power system stability; Dynamical system; Power conditioning circuits; Industrial equipment; Power supply quality; Voltage; Active filter; Voltage stability; Energy quality; Voltage dip; Electric fault; Voltage regulators; Control system; Power electronics; Hardware in the loop simulation; Power system restoration; Steady state; Phase locked loop; Power filters; Service quality; Power transmission line
• ISSN: 0378-7796; 1873-2046
• DOI: 10.1016/j.epsr.2011.10.002

Power quality is a very important topic nowadays. Sensitive industrial equipment should be protected against steady-state distortions and temporary transients in the distribution lines. Typical disturbances that affect the voltage waveform quality are harmonics, imbalances and sags. This paper presents a solution to protect sensitive loads against voltage disturbances that is based on a series power line conditioner. The goal of the proposed design is that the load does not suffer considerable input voltage variations. To achieve that, a Proportional-Resonant (PR) controller and a reference generator block based on a low-gain PLL are used, which avoids a sag detection block. Furthermore, a frequency adaptation loop is included in the PR controller, which provides a proper controller operation even with utility grid frequency deviations. Finally, a hardware in the loop (HIL) test rig is used to validate the system.