The cylindrical object on the left [of the placemark] houses a multi-million volt (MV) high voltage impulse generator (called a Marx Generator) at the Siberian Power Research Institute (SIBNIIE) high voltage testing facility in Novosibirsk, Siberia. The rate of rise of the voltage pulse from the Marx Generator was adjusted to maximize the "efficiency" of long spark propagation. Although first reports of huge 100+ meter sparks were initially met with skepticism by scientists and high voltage engineers, a number of power engineers and scientists have subsequently witnessed similar events at this facility. Sometimes these bolts hit the top of street lamps in the adjacent parking lot! Ultra long sparks of up to 200 meters long have been created using a (comparatively low) potential of 5.2 MV. In order to gain a feel for scale in the above photo, the cylindrical building is 28 meters (~92 feet) high, and it houses a 28-stage Marx generator that's capable of generating positive or negative output pulses of up to 7 MV.
In late 2005, a member of the Tesla Coil Mailing List (Dmitry, a Tesla Coiling enthusiast who lives near the facility) was able to schedule a visit with members of their staff. Dmitry subsequently shared details about this facility in a series of email messages to the other members on the list, and the excellent pictures he took can be seen on Terry Fritz's site. Through his efforts, we now know that the SIBNIIE generator uses 896 energy storage capacitors, each rated at 175 nF @ 125 kV. Each Marx stage uses thirty two capacitors connected in series-parallel and rated at 1400 nF at 250 kV. The fully charged "erected capacitance" is 50 nF and, at peak power, the generator can develop 1.225 Million joules per shot. In the above discharge, the maximum voltage was approximately five million volts, resulting in a point to point discharge of ~70 meters (230 feet). The estimated actual spark channel distance was ~150 meters (~492 feet). The pulse rise time was ~150 usec, duration was ~10 msec, and the overall Marx bank energy was ~678 kiloJoules.
Through research at facilities such as these, it has been determined that switching surges on Extra High Voltage (EHV) transmission systems can initiate streamers (conductive plasma channels) which can then lead to flashovers to another phase or to ground, causing circuit breaker trips and unplanned outages. Streamer formation and growth is presently the major limiting factor in practical EHV power transmission system design. This phenomenon constrains maximum transmission voltages to about 1.2 million volts. The highest operating AC transmission voltage is 1.15 million volts (a 696 kilometer transmission line that connects hydropower generating plants in Western Siberia, through Kazakhstan, to Russia).
Category: Scientific - Misc