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PureWave<sup>®</sup> DSTATCOM Distributed Static Compensator

PureWave® DSTATCOM Distributed Static Compensator

S&C’s PureWave DSTATCOM Distributed Static Compensator is a fast-compensating reactive power source that’s applied on the transmission or distribution system to reduce voltage variations such as sags, surges, and flicker, along with instability caused by rapidly varying reactive power demand. PureWave DSTATCOM can also help provide quick recovery for the transmission system after contingency events such as loss of part of the system or individual equipment.

Features

PureWave DSTATCOM is well suited to a major goal of the Smart Grid: Integration of renewable energy sources, such as wind, concentrated solar, and tidal power generation. It allows these renewable energy sources to meet utility interconnection requirements, as well as the power factor, voltage output, and low-voltage ride-through requirements of various worldwide grid codes.

PureWave DSTATCOM has been applied on a number of utility systems and wind farms since the late 1990s, meeting or exceeding all specifications.

  • Ultra-fast response time: 3 to 6 milliseconds. Provides faster voltage (or VAR, or power factor) control to enhance system voltage stability.
  • Substantial short-time capability for contingency events. Each inverter section can provide up to 3.3 MVAR for 3 seconds.
  • Modular design provides redundancy. Each 1.25-MVAR inverter has its own independent controls and circuit breakers, maximizing system reliability and availability. Individual inverters can be maintained while the remainder of the system is in operation. Inverters are air-cooled — not water-cooled — eliminating maintenance, enhancing reliability.
  • Packaged in compact ISO-style container. Minimizes need for valuable substation space. Up to four containers can be paralleled for a total system output of ±40 MVAR.
    • Includes climate-controlled control room with air-conditioning, if required. Weatherproof maintenance aisle enhances reliability and serviceability.
    • Flexible system sizing with control of external devices. Up to six externally switched capacitor or reactor banks can be controlled by PureWave DSTATCOM
    • Fully factory-tested for quick installation and commissioning.

PureWave DSTATCOM installation. PureWave DSTATCOM installation.

 

Ratings

The PureWave DSTATCOM Distributed Static Compensator utilizes ±1.25 MVA / 3.3 MVAR PWM Inverters in a modular arrangement.

Specifications
System Voltage Continuous Output 480 V to 35 kV, 50 or 60 Hz
Short-Term Current Rating 264% for 2 seconds, ramping to 100% at 4 seconds; or
264% for   seconds, stepping directly to 100%
Reactive Current Response Time 2 to 4 milliseconds
Inverter IGBT, pulse-width modulated at 4860 Hz
Temperature Range -40° to +50° C
Efficiency >98% typical
Cooling Ambient air cooling

  Single transformation to 46kV.

 

Dimensions and Weights of Pre-Packaged ISO-Style Enclosures (Typical)
System Rating,
MVAR
Number of Containers Dimensions, Feet (Meters) Weight,
Pounds (kg)
L W H
5.0 1 40 (12.2) 8.0 (2.4) 9.5 (2.9) 36,000 (16,364)
7.5 1 45 (13.7) 8.0 (2.4) 9.5 (2.9) 48,000 (21,818)
10.0 Container 1: Lead, 10 MVAR
Container 2: Control
45 (13.7)
20 (6.1)
8.0 (2.4)
8.0 (2.4)
9.5 (2.9)
9.5 (2.9)
48,000 (21,818)
14,000 (6,363)
15.0 Container 1: Lead and Controls, 7.5 MVAR
Container 2: Auxiliary, 7.5 MVAR
45 (13.7)
40 (12.2)
8.0 (2.4)
8.0 (2.4)
9.5 (2.9)
9.5 (2.9)
48,000 (21,818)
36,000 (16,364)

 

How It Works

The equivalent circuit of a power system with a PureWave DSTATCOM is shown below.

PureWave DSTATCOM generates a variable voltage, Vd, that is very nearly in phase with the source voltage, Vs. The inductance in this simplified circuit, L, consists of the inductance of the coupling transformer and filter. The voltage across the inductance, VL, equals Vs-Vd and is small in per-unit terms . . . on the order of 5-20%.

If Vs > Vd, VL is in phase with Vs and current IL lags Vs by 90°; PureWave DSTATCOM, acting as a generator, produces leading (inductive) reactive current.

If Vs < Vd, VL is antiphase with Vs and current IL leads Vs by 90°; PureWave DSTATCOM produces lagging (capacitive) reactive current.

Equivalent circuit of a power system with a PureWave DSTATCOM