Three-phase high voltage power supply design for electrostatic precipitator based on phase sequence self-adaption and redundant spark detection
The three-phase power supply has the advantages of small voltage ripple, balance three-phase load and high output power. It is suitable for application in the large electrostatic precipitators of the sintering machine head and the coal fired boiler. This paper designs the three-phase power supply based on phase sequence self-adaption and redundant spark detection. The winding connection mode of Y-Y and the full-bridge rectification circuit are used. This is beneficial to the energy saving, and the energy saving effect is also analyzed. In addition, the three-phase intermittent control is realized. The comparative experiments of voltage boosting between the three-phase power supply and the single-phase power supply demonstrate that the proposed design is effective.
A new method for detecting spark in electrostatic precipitation
Spark detection is an important problem in electrostatic precipitation. This paper proposes a new method for detecting the spark based on the load voltage variety. In order to obtain this variety, the control model of the power supply is established, and then the mathematical expression of the load voltage can be formulated. By analyzing the features of the spark breakdown, it is observed that the load voltage variety during the spark breakdown is much larger than that of normal condition. Therefore, the maximum variety of the load voltage under normal condition can be considered as the detection threshold. In addition, the control method which tracks the dielectric strength recovery curve is also presented. The simulations and experiments demonstrate that the proposed method is effective.
Spark protection circuit for measuring current in high-voltage circuits
Abstract A circuit has been designed to protect electrometers and other sensitive instrumentation from damage by electrical sparks. Measuring current is necessary in a variety of high-voltage applications, including the evaluation of ionizers designed to eliminate static charge. The currents are often small, perhaps only several microamperes (μA) or less. Instruments designed to accurately measure such small currents are expensive and sensitive. Consequently, the instruments are susceptible to damage from unexpected electrical sparks that are common in high-voltage experiments. The protection circuit has two layers of protection. The first layer is a Zener Transient Voltage Suppressor that limits the input voltage by shunting the spark energy to ground potential. The second layer of protection is a passive, low-pass filter that blocks the high-frequency energy of the spark while passing the low-frequency current to be measured. The filter design is based on a resistively terminated, LC Cauer network. Three inductors are required to obtain high-frequency attenuation exceeding 10 +6 , resulting in a sixth-order low-pass filter. Small resistances to ground through connectors and cables, that are normally negligible, limit the high-frequency attenuation to about 10 +5 , which provides sufficient protection.