PCS-9575 — thyristor static frequency converter (SFC/LCI) for starting pumped-storage motor-generators and gas turbines
NR PCS-9575 is a static thyristor frequency converter (SFC), also known as a load-commutated inverter (LCI), with 6- or 12-pulse bridges. It performs frequency starting and speed control of large synchronous machines. It is used at pumped-storage plants, gas turbine power plants and industrial enterprises with powerful synchronous motors.
- Purpose
- frequency starting and speed control of large synchronous machines (pumped-storage motor-generators, gas turbine generators, synchronous motors)
- Circuit
- current source: rectifier — smoothing reactor — inverter, three-phase thyristor bridges
- Pulse number
- 6 or 12 (rectifier and inverter)
- Thyristor control
- photoelectric, TCU
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
The converter quickly accelerates the machine to the required speed and, if needed, holds it at the set rotational speed. At pumped-storage plants it starts reversible motor-generators in pumping mode, and at gas turbine stations it spins up the gas turbine through the generator operating as a motor. In function the PCS-9575 corresponds to the thyristor starting devices supplied together with pumped-storage motor-generators.
The power part is built on a current source scheme. The input switchgear with circuit breakers connects the unit to the grid. The input transformer limits the short-circuit current, provides galvanic isolation and the required secondary voltage. Depending on the pulse number and the voltage ratio, three-winding or two-winding step-down or isolating (1:1) transformers are used. The rectifier is a three-phase thyristor bridge with 6 or 12 pulses, with photoelectric control through TCU units and water or air cooling.
An air-cooled smoothing reactor reduces ripple and limits the short-circuit current in the DC link. In a number of projects, reactors are additionally fitted at the input and output. The inverter is also a three-phase thyristor bridge with 6 or 12 pulses. The output transformer matches the output voltage to the stator voltage and isolates the SFC from the machine; in the LCI scheme it is absent. The output switchgear contains the output breaker and the transformer bypass breaker.
For small and medium power, cooling is forced air. For large power the manufacturer uses a closed water system based on its own patented technology, with a separate control system. The valves are compact and the cooling system is simple, so servicing is inexpensive.
The control and protection system runs on a distributed multiprocessor platform with high noise immunity and is programmed with visual modules. It collects analog and discrete data, generates switching commands and firing pulses, and regulates frequency stably. Real-time phase auto-adjustment gives stable pulses. Differential protections, overcurrent protection, protection by rate of current rise, fault recording and analysis, external data exchange and a convenient operator interface are provided. The pulse number of the bridges, the type of transformers and the cooling method are chosen for the specific machine and grid.
Technical specifications
| Purpose | frequency starting and speed control of large synchronous machines (pumped-storage motor-generators, gas turbine generators, synchronous motors) |
|---|---|
| Circuit | current source: rectifier — smoothing reactor — inverter, three-phase thyristor bridges |
| Pulse number | 6 or 12 (rectifier and inverter) |
| Thyristor control | photoelectric, TCU |
| Transformers | input and output (2- or 3-winding, step-down or 1:1); in the LCI scheme the output transformer is not used |
| Cooling | forced air (small/medium power) or closed water (large power) |
| Protections | differential, overcurrent, di/dt |
Request a price and lead time
PCS-9575 — thyristor static frequency converter (SFC/LCI) for starting pumped-storage motor-generators and gas turbines. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Customs codes
| UKTZED (Ukraine) | 8504 40 88 00 |
|---|---|
| HS, 6 digits | 8504 40 |
| CN (EU) | 8504 40 88 |
| HTSUS (USA) | 8504 40 95 80 |
| China customs tariff | 8504 40 99 99 |
Codes are for reference: the final code is determined at declaration for the specific model.
Questions and answers
What machines is the PCS-9575 intended for?
For frequency starting of reversible pumped-storage motor-generators, gas turbine generators and powerful synchronous motors. It also maintains the set rotational speed.
What pulse number do the rectifier and inverter have?
Both are three-phase thyristor bridges with 6 or 12 pulses. The thyristors are controlled photoelectrically through the TCU.
How does the LCI scheme differ from an SFC with an output transformer?
In the LCI scheme no output transformer is used. Otherwise it matches the output voltage to the stator voltage and isolates the converter from the machine.
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