RTX POWER 4Q — four-quadrant excitation system for synchronous condensers 10–300+ MVA
RTX POWER 4Q is the four-quadrant version of the RTX POWER excitation system for synchronous condensers rated from 10 MVA to over 300 MVA. A power section of two anti-parallel thyristor bridges allows operation with zero and negative field current. Such systems are installed at substations, near large solar and wind plants, and in the transmission and distribution network.
- Application
- synchronous condensers (operation with zero and negative field current)
- Condenser power
- from 10 MVA to over 300 MVA
- Power circuit
- two three-phase Graetz bridges anti-parallel (positive and negative)
- Quadrants
- I–IV (field current reversal)
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
A synchronous condenser does not produce active energy and does no mechanical work. It adds inertia and short-circuit power to the power system and takes part in voltage and reactive power regulation. The greater the share of solar and wind generation, the more such machines are needed. According to the manufacturer, condensers range from 10 MVA to over 300 MVA, mostly salient-pole and less often with a cylindrical rotor. They are installed at substations, next to large solar and wind plants, in the transmission and distribution network and at industrial sites.
A salient-pole machine can operate with zero and even negative field current. For this, the power section of RTX POWER 4Q is built from two three-phase Graetz bridges connected anti-parallel. The positive bridge supplies forward field current (quadrant I) and, during transients or self-excitation, briefly works with negative voltage (quadrant II). The negative bridge carries reverse current and likewise can temporarily work with positive voltage (quadrants III and IV). The most delicate point of the scheme is accurately detecting the complete extinction of current in one bridge before firing pulses are applied to the other. A switching error causes a short circuit in the converters and fuse operation. The manufacturer states that it owns the current reversal technology, and RTX POWER regulators work on the largest machines in Latin America.
Control, regulation and limiting functions, communication and commissioning tools are the same as in the base RTX POWER. These are the CPX06 controller, TTM01 modules, functions according to IEEE 421.5, and the IEC 61850, DNP3.0, IEC 60870-5-101/104 and Modbus protocols. If condenser starting must also be controlled, the combined RTVAX POWER system is used.
At the Santo Ângelo and Embu-Guaçu substations in Brazil, two 250 MVA, 10 kV condensers each are in operation. Their rated field current is 2302 A, the reverse current −194 A, the field voltage 212 V, and each system has three positive and two negative bridges and field breakers on the AC and DC sides. At the Marmeleiro II substation there are two 110 MVA, 13.8 kV condensers with a field current of 1800 A (reverse −180 A) and a voltage of 240 V. Typical sites for RTX POWER 4Q include system-forming and distribution substations, renewable connection nodes and industrial networks.
Technical specifications
| Application | synchronous condensers (operation with zero and negative field current) |
|---|---|
| Condenser power | from 10 MVA to over 300 MVA |
| Power circuit | two three-phase Graetz bridges anti-parallel (positive and negative) |
| Quadrants | I–IV (field current reversal) |
| Example Santo Ângelo/Embu-Guaçu | 2 × 250 MVA, 10 kV, Iexc 2302 A (−194 A), Uexc 212 V; 3 positive + 2 negative bridges |
| Example Marmeleiro II | 2 × 110 MVA, 13.8 kV, Iexc 1800 A (−180 A), Uexc 240 V |
| Platform | as RTX POWER (CPX06, TTM01, IEEE 421.5) |
Request a price and lead time
RTX POWER 4Q — four-quadrant excitation system for synchronous condensers 10–300+ MVA. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
What machines is RTX POWER 4Q designed for?
For synchronous condensers rated from 10 MVA to over 300 MVA, mostly salient-pole. The system works with zero and negative field current in all four quadrants.
How is the power section of the four-quadrant excitation built?
It is built from two three-phase Graetz bridges connected anti-parallel. The positive bridge supplies forward field current, the negative one reverse current, and pulses are applied to the other bridge only after the current in the first has fully extinguished.
What parameters do the implemented projects have?
At the Santo Ângelo and Embu-Guaçu substations, 2 × 250 MVA, 10 kV condensers with a field current of 2302 A are in operation. At Marmeleiro II, 2 × 110 MVA, 13.8 kV, 1800 A and 240 V are installed.
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