Chapter 3. Power System Harmonic Mitigation. INTRODUCTION. Power system harmonic issues have existed since the early 1900 ’ s. The earliest discovered issues were third harmonic currents produced by saturated iron in machines and transformers.
Power System Harmonic Mitigation
Using blockade device to blockthe flow of the third harmonic current in the neutral conductorand measure the energy consumption at the primary of one of the above transformers over repeated 15 minute intervals, first with and then without the blockade in the circuit.
Figure 1: Single Line of Building Distribution System
The instrument used is a Yokogawa WT2030, which is a lab-grade power analyzer connected on the primary side.
Blockade device reduces the Neutral-to-Ground Voltage 66.30%which is clear by the following table
If hr is close to a characteristic harmonic, such as the 5th or 7th, there is a possibility that a harmful resonant condition could occur.
Pseudo 12-pulse systems: This configuration uses phase-shifting transformers to cancel 5th and 7th harmonics at the common bus. For cancellation to occur, the non-linear loads must be operated simultaneously and have similar characteristics. One cost-effective