VHSC 150 / VHSC 300 — synchronous condensers up to 300 Mvar
VHSC 150 and VHSC 300 are horizontal salient-pole synchronous condensers rated up to 300 Mvar in overexcited mode. They run in the grid without a driving turbine and support its stability with reactive power, inertia and short-circuit current. The machines are installed at substations at the end of long lines, at critical grid nodes, at HVDC converter stations and near large energy-intensive consumers.
- Models
- VHSC 150, VHSC 300
- Output in overexcited mode
- VHSC 150: 125–165 Mvar; VHSC 300: 225–300 Mvar (depending on frequency and cooling)
- Rated voltage
- VHSC 150: 11.5 / 13.8 kV; VHSC 300: 12.5 / 15 kV (50/60 Hz)
- Rotational speed
- 750 rpm (50 Hz), 900 rpm (60 Hz)
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
The share of wind and solar plants is growing, conventional units are being retired, and the grid lacks reactive power, inertia and short-circuit power. A synchronous condenser closes these gaps. Unlike static devices, it adds physical inertia to the system and keeps the rate of change of frequency (RoCoF) low. The short-circuit current reaches five times the rated current, so protection operates correctly. By adjusting the excitation, the machine moves smoothly from supplying reactive power to absorbing it, and when the voltage drops its reactive power output rises. The short-time overload is 1.5 times the rated current for 30 s.
The salient-pole rotor, according to the manufacturer, gives a higher moment of inertia, lower losses, a wider underexcitation range and lower vibration than machines based on turbogenerators with a cylindrical rotor. A hydrogen atmosphere is not required. Standard machines are unified for 50 and 60 Hz, with active parts of identical dimensions, number of slots, bars and poles. The rotational speed is 750 rpm for 50 Hz and 900 rpm for 60 Hz, and the insulation is of thermal class 130.
Cooling is by air in an open circuit, when the machine stands in a building with louvres, filters and silencers, or in a closed TEWAC circuit with air coolers and dry or wet cooling towers. Only TEWAC is suitable for outdoor installation. Excitation is static, Thyricon 500, starting is performed by a static frequency converter SFC, and one SFC starts several machines in turn. For greater inertia, a flywheel on its own shaft with two bearings is fitted; it rotates in air at atmospheric pressure. The inertia constant H without a flywheel is 1.9–3.5 s, with a flywheel up to 10 s and more.
VHSC 150 delivers 125–165 Mvar depending on frequency and cooling; with an open circuit this is 135/165 Mvar for 50/60 Hz. The short-circuit power on the HV side of the unit transformer for it is 525/625 MVA. VHSC 300 delivers 225–300 Mvar, and for 50/60 Hz in the same design 250/300 Mvar, with a short-circuit power of 1050/1250 MVA. The rated voltage of VHSC 150 is 11.5/13.8 kV and of VHSC 300 12.5/15 kV; the overall application range exceeds 300 Mvar. Design and tolerances comply with IEC 60034-1, 60034-3 and 60034-33. References include the Riel substation in Canada with 4 machines of −125/+250 Mvar and a number of substations in Brazil at −90/+150 Mvar.
Technical specifications
| Models | VHSC 150, VHSC 300 |
|---|---|
| Output in overexcited mode | VHSC 150: 125–165 Mvar; VHSC 300: 225–300 Mvar (depending on frequency and cooling) |
| Rated voltage | VHSC 150: 11.5 / 13.8 kV; VHSC 300: 12.5 / 15 kV (50/60 Hz) |
| Rotational speed | 750 rpm (50 Hz), 900 rpm (60 Hz) |
| Overload | 1.5 × rated current for 30 s |
| Inertia constant H | 1.9–3.5 s without flywheel; up to 10 s with flywheel |
| Cooling | air, open circuit or TEWAC (water ≤ 30 °C / dry cooling towers) |
| Insulation | thermal class 130 |
| Excitation | static Thyricon 500; start by SFC |
| Standards | IEC 60034-1, IEC 60034-3, IEC 60034-33 |
Request a price and lead time
VHSC 150 / VHSC 300 — synchronous condensers up to 300 Mvar. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
What reactive power do VHSC 150 and VHSC 300 deliver?
In overexcited mode VHSC 150 delivers 125–165 Mvar and VHSC 300 delivers 225–300 Mvar, depending on frequency and cooling. The overall application range exceeds 300 Mvar.
What overload and short-circuit current does the synchronous condenser provide?
The machine withstands 1.5 times the rated current for 30 s. The short-circuit current reaches five times the rated current, so grid protection operates.
How is the condenser inertia increased?
Without a flywheel the inertia constant H is 1.9–3.5 s. A flywheel on its own shaft with two bearings raises it to 10 s and more.
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