Automatically switched harmonic filter/power factor corrections systems.
- Programmable to automatically add/subtract filter banks to maintain preset target power factor
- Filter steps tuned for maximum efficiency in reducing harmonic currents in three-phase environments with heavy nonlinear loads
- Efficient modular design for short lead times, ease of maintenance and ease of future expansion
- Heavy-duty, three-phase capacitor construction with reliable, threaded terminal connections
- Cool operating, 100% copper wound, thermal protected reactors are sized up to 150% of rated capacitor current
Application Description
Service entrance power factor correction installations requiring precise maintenance of target power factor in three-phase, nonlinear, high harmonic environments.
Features
Configuration
- Operation: AUTOVAR harmonic filters are designed to be sized the same as any power factor correction unit. In most low voltage applications where harmonics are generated by nonlinear loads, no harmonic audit is necessary to design the AUTOVAR filter because it is already designed for typical harmonic spectrums at the kVAR size specified
- Cabinet: 12 gauge steel with ANSI 61 gray, baked enamel finish. Lift bolts standard, NEMA 1
- Power line interconnect: Rugged, copper bus bar connection with access provided for top or bottom entry. Bus bars are braced for 65 kAIC at 480V. All internal power wiring connections from bus are laid out on a most direct basis with minimum bends for ease of troubleshooting. Clear barrier limiting access to live parts included standard
- Modular tray design: Capacitor banks arranged in modular trays with capacitors, fuses, blown-fuse indicating lights, and contactors grouped in a logical, easily under-stood layout. This permits easy access, quick identification of operating problems and ease
of expandability - Fusing: UL recognized, 200,000A interrupting capacity provided on all three phases of each bank. Blade-type fuses mounted on insulator stand-offs
- Blown-fuse lights: Blown-fuse indicating lights located on the door-mounted blown and at individual fuses to facilitate tracing of cleared fuses
- Push-to-test: Allows testing of door-mounted blown fuse indicating lights
- AutoLocate: When door is open and bus energized, fuse circuit automatically checks for cleared fuses. If a fuse has cleared, the light at the fuse comes on for easy troubleshooting
- Door interlock: Door interlock automatically turns off control circuit when engaged. Power continues to be provided to the unit until disconnect is open
- Exhaust fans: Two fans per cabinet provide thermal protection. Dust filtering provided
- Ease of expansion: Capacitor stage nests are self-contained and can be added in the field. Control wire plugs connect to factory standard wire harness on the left side of the cabinet
- Ease of replacement: Cells can be easily individually replaced by removing the mounting bolt and lifting out of the nest without removal of any other components
Controller
- Visual indication of incorrect CT polarity
- Digital display of power factor and number of energized banks
- Automatic setting of c/k value (sensitivity based on CT ratio and kVAR available)
- Alarm on failed step
- Visual indication of insufficient kVAR to reach target power factor
- Capacitors disabled in steps within 35 milliseconds of main power interruption
- Automatic sensing of kVAR values per step
- Optional communications capable (RS-485/Modbus) controller
- Optional metering capability:
- Voltage
- Current (sensed phase only)
- Frequency
- Active power (kW)
- Reactive power (kVAR)
- Apparent power (kVA)
- Optional thermostatic control exhaust fans
Contactor
- Fully rated for capacitor switching up to 60 kVAR at 600V
- Integral pre-charge/pre-insertion module standard. The contactor reduces damaging switching transients. This provides safety and durability for the system:
- Lessens the chance of disrupting sensitive electronic equipment
- Reduced inrush current extends the life of the capacitor cells
Reactors
- Tuning: Reactors tuned to the 4.7th harmonic order (nominal 5th). This provides maximum effectiveness in reducing harmonic currents in threephase systems with harmonics caused by 6-pulse devices
- Detuning: Reactor designs can be detuned upon request (4.2nd, 6.7th for example) to protect capacitors against alternate harmonics
- Windings: 100% copper windings for minimal temperature rise under load
- Thermal overload protection: Each reactor includes three normally closed, auto reset thermostats that open at 180°C. When thermostats engage, the contactor opens
- Insulation: 220°C insulation system
- Warranty: One-year replacement of reactors
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