Loading...
Please wait, while we are loading the content...
Similar Documents
Elimination of Neutral Current Harmonics in Three- Phase Four-wire Distribution System
| Content Provider | Semantic Scholar |
|---|---|
| Author | Sabarivelu, V. Ambika, Kohli Brintha, A. |
| Copyright Year | 2014 |
| Abstract | Power Quality is an important problem a Power System has to handle to provide its consumers a reliable and economical supply. Three-phase four-wire distribution systems have been widely used in commercial and industrial installations. In the three-phase four-wire distribution systems, the neutral current carries the zero sequence current due to the unbalanced loading among the phase conductors. Due to the presence of power electronics load a triplen (third, ninth, etc) harmonics are introduced in the system. This project uses a new harmonic suppression scheme for the neutral conductors of three-phase four-wire distribution systems. This new scheme consists of a series active filter, which is connected in series with the neutral conductor to suppress the harmonics in the neutral conductor. This new filtering technology scheme consists of a voltage source inverter in series with the series connected inductor and capacitor set. This scheme is implemented for a system feeding a non-linear loads and its performance is tested. The results show that the proposed scheme is suitable for practical applications. Index Terms—Harmonic voltage distortion, series active filter neutral conductor, third harmonics. I. INTRODUCTION Electric Power becomes a most basic need in our day-to-day life. Electric utilities aim is to provide a consumer a good quality of reliable continuous power supply at economical cost. In three-phase four-wire distribution system, due to use of non-linear loads, excessive current will flow in the neutral conductor. In most three-phase power systems supplying single-phase loads, there will be some phase current imbalance and some neutral current. Under normal operating conditions with reasonably balanced load, the current in the neutral is expected to be 20% of the normal phase currents. Especially on three-phase four-wire distribution systems, the third-harmonic currents are increased. The excessive third harmonic currents cause overheating of the neutral conductors. Hence, voltage distortion on utility outlets and excessive neutral current on distribution lines have arisen and lead to a number of serious problems in the distribution system. These neutral currents are fundamentally third harmonics and odd multiples of 3rd due to non- These harmonics can be eliminated by using Passive filters (Combination of L and C). These types of filters have disadvantages of series resonance, parallel resonance, tuning of passive elements is difficult, etc.Recently, harmonics suppression facilities based on Power Electronics techniques have proved to be important. This harmonics suppression can be done with the help of new emerging Series Active Power Filters. This Series Active Filters (SAF) is connected in series with the neutral line to reduce the harmonics in the neutral line. This has more advantages when compared to the other configurations. The followings are the advantages of connecting series active filters in series with the neutral line. • It is very less complexity and less economical • It has small rating normally 4% of the load KVA • It acts as a harmonic isolator between the supply and the load • It is more economical for harmonic compensation of the large no-linear loads • It prevents supply-load interaction and resonance problem • It can adapt to changing the load condition. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.techscripts.org/may_2014/may201411.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
