van der Pct Piet Laan

Hot biogas conditioning using pulsed corona

A new technology area for pulsed corona is hot biogas cleaning, important in view of the growing interest in biomass gasification. Our work concentrates on the development and optimization of pulsed electrical methods for treatment of thermally generated biogas. Corona energized by narrow voltage pulses (100 kV) makes a well ordered and concentrated deposition possible of electrical energy from a circuit into a hot polluted gas. The created plasmas can break down various contaminants. Successful introduction of pulsed corona for industrial processes very much depends on the reliability of high-voltage and pulsed power technology and on the efficiency of energy transfer. In addition, we must achieve adequate electromagnetic compatibility (EMC).

Prevention of breakdown due to overvoltages across interruption of GIS enclosure

Voltage transients generated in GIS by the operation of circuit breakers or disconnect switches induce high voltages across interruptions of the enclosure. In this paper we discuss such interruptions and their necessity. We present fast measurements of voltage and current at the GIS/cable-interface of a 150 kV substation, where the enclosure is interrupted to permit current measurement. Circuit breaker operation causes a single voltage transient across the interruption with an amplitude up to 40 kV, a duration of 200–300 ns, and a risetime of about 5 ns. Disconnect switch operation causes multiple transients, each having a smaller amplitude and a longer risetime. The voltage across enclosure interruptions is adequately suppressed, and breakdown is completely eliminated, when the interruption is bridged with resistors. The resistors do not affect the current measurement.