THYRISTOR SWITCHED HARMONIC FILTER BANKS...
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NEPSI's actiVARTM, Medium Voltage Metal-Enclosed Thyristor Switched Harmonic Filter Banks are custom designed for power systems requiring instantaneous var support to mitigate voltage sags, voltage flicker, and high inrush currents associated with starting and impact loading of large motors and dynamic loads. This equipment stabilizes your system voltage, helps your equipment run more smoothly, and increases your systems efficiency and throughput.
Hybrid designs are available that include NEPSI’s well known and reliable mechanically switch harmonic filters to economically increase the benefits of this product to include power factor correction and harmonic distortion attenuation.
Thyristor valves used in the actiVARTM provide “fast vars” for voltage sag and flicker mitigation while standard capacitor switches provide “slow vars” for harmonic distortion attenuation and power factor correction.
The actiVARTM samples your phase voltage, load, and line currents at rates exceeding 7,000 times a second, analyzing them in real-time, and instantaneously responds to abnormalities in real-time. Changing state 60 times a second, the actiVARTM effectively stiffens your voltage supply. Industries using high dynamic loads such as welders, shredders, rolling mills, and arc furnaces benefit from this product and have seen paybacks in less than 1 year with improved plant productivity and power factor improvement.
The actiVARTM is available in voltages from 2.4kV through 24.9kV, with MVAR ratings from 0.5 MVAR to 100 MVAR. The actiVARTM is designed for placement in outdoor or indoor substations and come fully assembled, tested, and ready for interconnection.
...FOR VOLTAGE SAG & VOLTAGE FLICKER MITIGATION
With single-cycle response times, the actiVARTM mitigates voltage sag and voltage flicker, allowing large dynamic loads to operate efficiently while greatly reducing their impact on the power grid. The actiVARTM can dramatically lower both customer and utility investments - while providing customers improved performance levels.
The following table summarzies the many features and benefits of applying the actiVARTM to your system.
Provides near instantaneous mitigation of voltage sags and voltage flicker, resulting in a near perfect voltage profile.
The near perfect voltage profile allows for more efficient operation of your equipment; - allowing for higher production levels and throughput.
Transient Free Operation, eliminating adverse effects of switching transients.
Power Factor Correction
& Harmonic Filtering
Corrects plant power factor, reducing KVA and power factor penalties, increasing system capacity, while improving your voltage profile.
Reduces plant voltage and current distortion. Designed for compliance with IEEE 519 harmonic distortion limits.
All-Inclusive Design - Equipped with integral disconnecting device, protection, and control.
Comes fully assembled, calibrated, tested, and ready for interconnection.
Enclosure protects key components from wildlife and atmospheric contaminants.
Easy to maintain
Designed and built by an ISO 9001:2008 certified company with a proven track record of quality and performance.
Safety - Enclosure prevents inadvertent contact.
Key Interlock System
Safety and proper sequence of operation
Easy to purchase.
Fully integrated design
NEPSI's actiVARTM is rated and configured to meet customer requirements for voltage, basic insulation level (BIL), available short circuit current, reactive power rating, and frequency. Internal components such as disconnect and grounding switches, circuit breakers, capacitors, capacitor switches, thyristor valves, and capacitor fuses are chosen based on their ratings, costs, availability, and NEPSI's experience with the supplier's quality, service, and reliability.
RANGE OF AVAILABLE RATINGS
|Bank Configuration:||Thyristor Switched: Single Step/Multiple Step
Hybrid Design: Thyristor & static switched
|Filter Types:||Notch (Band-Pass), High-Pass, C-High-Pass, Multi-Tuned|
|Operating Voltage (line-to-line):||2.4kV – 24.9kV|
|Operating Frequency:||50 Hertz | 60 Hertz|
|Reactive power output:||0.5MVAR – 100 MVAR
(500kvar – 100,000 kvar)
|Tune frequency (Hz)||85 Hz 2100 Hz
(1.4th Harmonic – 35th harmonic)
|High-Pass (damping) resistor rating:||1 ohm to 1000 ohms
10kW/Phase - 200kW/Phase
|16kA - 61kA|
|Impulse withstand voltage
(Basic Insulation Level):
|60kV – 125 KV|
|Short-time withstand voltage
(1 minute 50/60 Hertz):
|19kV – 60kV|
|Control voltages:||AC Volts: 110, 115,120, 220, 50/60hz
DC Volts: 24, 48, 110, 125, 220
|Operating temperature range:||-50°C to +55°C
-58°F to 131°F
|Maximum altitude without de-rating:||1,000 Meters
|Enclosure:||(NEMA): 1, 3R, 4X, 12
(IEC): IP10, IP14, IP56, IP52
Arc Flash Mitigation: Passive & Active
Hazardous Locations: NEC Class 1 & 2, Div. II
|Seismic:||As specified - Zone 4|
|Capacitor fusing:||Internally fused | Externally fused|
SEMI (Semiconductor Equipment and Materials International), F47-0706, F49-0200, and F50-0200s
CBEMA (Computer and Business Electronic Manufacturers Association), curve referenced in ANSI/IEEE Std. 446-1987
ITIC (Information Technology Industries Council) tolerance curve
IEEE Standard 1346-1998, Recommended Practice for Evaluating Electric Power Systems Compatibility with Electronic Process Equipment
IEEE 1250-1995, Guide for Service to Equipment Sensitive to Momentary Voltage Disturbances.
IEC 61000-4-11 and 61000-4-34, (International Electrotechnical Commission)
IEEE Std. 1453, Table A.1, Recommended Practice for Measurement and Limits of Voltage Flucations and Associated Light Flicker on AC Power Systems
IEEE 519, Recommended Practices and Requirements for Harmonic Control in Electrical Power Systems
NEPSI's actiVARTM is custom designed, configured, and rated to mitigate voltage sags, flicker, harmonic distortion, and power factor. Depending upon the performance objectives of the equipment, the actiVARTM may come with one or more conventionally switched filter stages. Conventionally switched stages that use standard capacitor switches are less costly, provide "slow vars" for power factor correction and harmonic distortion. Thyristor switched stages, the key component of the actiVARTM, provide "fast vars" to mitigate voltage sags and voltage flicker.
The physical arrangement of the actiVARTM, including component layout, incoming compartment configuration, filter type, and tuning point are customized to meet site specific constraints and requirements.
Click each of the headings below to learn more about our actiVARTM configurations.
INCOMING COMPARTMENT CONFIGURATION OPTIONS
The incoming compartment, where power is connected to the equipment, is normally configured based on the availability of existing breakers, disconnect switches, and the rating of the thyristor switched harmonic filter bank. Typical configurations options are provided below.
ACCESSORIES FOR INCOMING COMPARTMENT
The following items are available for placement in the incoming compartment.
THYRISTOR SWITCHED STAGE CONFIGURATION OPTIONS - "FAST VARS"
Thyristor switched harmonic filter stages utilize thyristor valves to provide "fast" vars to mitigate voltage sags and voltage flicker. Due to their high cost, vars for power factor correction and harmonic filtering, if required, should use conventionally switched filter stages as provided under heading three below.
The Delta Valve configuration utilizes thyristor valves connected in a Delta configuration. Voltage ratings of the valves, reactors, and capacitors are rated based on the system line-to-line voltage rating. Current within the Delta is 57% of the current outside the Delta. Therefore, components within the Delta are rated at 57% of the expected line current. Details of this valve configuration are as follows:
For application on systems with line-line voltages of: 2.4kV – 13.8kV
Transient Current Limit: 500 amps (with or without fins)
Continuous Current Rating: 180 amps (with fins)
The Wye-Grounded valve configuration utilizes thyristor valves connected in grounded-wye configuration. Voltage ratings of the valves, reactors, and capacitors are rated based on the system's line-to-neutral voltage rating. Higher system application voltage ratings are possible with this configuration. Details of this valve configuration are as follows:
For application on systems with line-line voltages of: 2.4kV – 24.9kV
Transient Current Limit: 500 amps (with or without fins)
Continuous Current Rating: 180 amps (with fins)
Restriction: Valve configuration for grounded-wye system only. Resistance-grounded, high-impedance grounded, or Delta systems must use the delta connected valve configuration.
CONVENTIONALLY SWITCHED STAGE CONFIGURATION OPTIONS - "SLOW VARS"
Conventionally switched harmonic filter stages use standard capacitor switching technologies to economically provide "slow" vars for power factor correction and harmonic filtering. Standard capacitor switches do not respond fast enough to mitigate voltage flicker and voltage sags.
A conventionally switched harmonic filter bank stage consists of a capacitors, capacitor fuses, switching devices, and harmonic filter reactors. Typical filter bank stage configuration options are provided below. The filter bank stage compartment is compartmentalized and isolated from the incoming compartment to allow for maintenance and repair.
The harmonic filter stages can be connected in a number of different ways depending upon bank rating and protection requirements. Typically, harmonic filters are provided with an ungrounded wye or ungrounded split-wye connection, but a grounded wye and Delta connection are also available.
Component selection is based on specified control and protection requirements, thyristor switched and conventionally switched harmonic filter bank requirements, short circuit level, voltage, BIL, reactive power rating, frequency, costs, and NEPSI's experience with component quality and reliability. The following list provides key components and features commonly supplied by NEPSI.
Click each of the headings below to learn more about our commonly used components
Air Disconnect Switch
Externally operated chain-drive operated 3-pole air-disconnect switch to provide a "visible-break" and electrical isolation of the equipment during maintenance and repair.
Externally operated chain-drive or direct-drive operated 3-pole ground switch to ground the load-side terminals of the incoming air-disconnect switch, breaker, and/or capacitors for safety during maintenance. The ground switch is key interlocked with the upstream disconnecting device to prevent closing of the ground switch onto a live bus.
Main Incoming Fuses
Main incoming current limiting fuses (with local and remote blown fuse indication) for short circuit protection of the equipment.
Main Incoming Breaker
Main incoming drawout or fixed-mounted circuit breaker for protection, isolation, and switching of the equipment.
Lightning arresters are provided as standard on NEPSI's equipment to protect the actiVARTM and incoming cables from lightning and switching transients.
Control Power Transformer(s) (CPT)
Control power transformers to supply control power and voltage sensing to the thyristor switched filter bank's, metering, protection, and control system.
Current Transformers (CT)
Current tranformers to supply a current signal for the metering, protection, and control system.
Bus Duct Entry
Bus duct entry to allow for direct bus connection to switchgear.
Dead-front design entry that allows for 200 amp and 600 amp separable elbow connectors.
Roof Bushing Entry
Roof bushing entry to allow for direct connection to overhead bus within substations.
THYRISTOR & CONVENTIONAL SWITCHED FILTER COMPARTMENTS
Low loss, double bushing capacitors that meet or exceed IEC 871, IEEE 18 and CSA standards. Capacitors are typically connected ungrounded-wye or ungrounded split-wye for conventionally switched filter stages and wye-grounded and delta connected for thyristor switched harmonic filter stages. Internal discharge resistors reduce the residual voltage to less than 50 volts within 5 minutes of de-energization. The dielectric fluid is environmentally friendly, biodegradable, non PCB, with low toxicity. Internally fused capacitors are available upon request.
Capacitors are individually fused with current limiting fuses. These fuses reduce the possibility of case rupter on capacitor failure and allow the system to continue to operate when a capacitor fails. The fuses are equipped with blown fuse indicators and can also be equipped with direct fuse operation sensors for blown fuse detection.
Thyristor Switched filter stages utilize oil-cooled and insulated thyristor valves to accomplish single-cycle, transient free switching.
Conventionally switched harmonic filter stages are equipped with vacuum contactors (for voltages less than 6.6kV), capacitor switches, or circuit breakers (fixed or drawout) for stage switching.
Iron Core Filter Reactors
Iron-core filter reactors provide the necessary inductance (inductive reactance) to tune the conventionally switched and thyristor switched stages to the desired frequency. In addition to tuning, the reactors significantly reduce the frequency and magnitude of the switching transient.
High Pass Filter Resistors
Stainless steel Grid Reistors are provided for C-High Pass, High-Pass, and Double-Tuned conventionally switched harmonic filter stages. Resistors are of a stainless steel stamped grid design that offer compact high wattage capability, low temperature coefficient, and corrosion resistance.
Harmonic filter stages can be equipped with current transformers to provide a current signal for metering and protection. Current transformers can be provide to monitor both iron-core reactor current as well as high-pass resistor current.
Air Disconnect Switch
Externally operated, key interlocked, 3-pole air-disconnect switch(s) that isolates a single stage of a multi-stage filter bank, allowing for partial bank operation during maintenance.
Externally operated, key interlocked, 3-pole ground switch(s) that grounds the capacitor terminals to ensure all trapped charge has been removed from the capacitors.
CONTROL AND PROTECTION COMPARTMENT
The actiVARTM is equipped with a speciallized microprocessor controller that has the necessary speed and software for controlling the thyristor valves for voltage and flicker mitigation. The controller also incorporates the conventionally switched harmonic filter stages for power factor correction.
Thyristor Switched and conventionally switched filter stages may be equipped with various protection relays, meters, and sensors to protect the filter stages as well as the system from over-voltage, out-of-balance operation from capacitor failure, internal faults, and over-temperature due to fan failure. Protection devices are integrated with the actiVARTM controller to form a fully integrated system.
Arc Flash Mitigation
See NEPSI’s technical note on arc flash mitigation in metal-enclosed capacitor banks and harmonic filter banks. This technical note provides over 30 mitigation strategies available from NEPSI to minimize the level of exposure to arc flash events as well as ways to reduce the probability that an arc flash event will occur in the first place.
Free standing, compartmentalized, all welded, 11 gauge galvanneal steel construction with 3 point pad-lockable latching handles and stainless steel hinges. The enclosure is painted with Engineered Siloxane, a Marine paint with rated salt spray of 5500 hours. NEMA 3R (IP64) construction is standard, NEMA 12 (IP65) and 4X (IP66) are available as an option. Base of enclosure as well as capacitor supports are formed from C4 structural steel. Door stays and windows are standard.
Key Interlock System
Key interlock system are available that dictate sequence of operation and safe entry into the enclosure. Upstream devices may be included in the interlock sequence.
Ground and Phase Bus
A 1/4" X 2" Tin plated ground bus is provided through the width of the enclosure to assist in grounding during maintenance. All phase bus is Tin plated square edged and rated at a minimum of 135% of the bank nominal current rating.
NEPSI's actiVARTM is furnished with an integrated control and protection system that is located in an isolated compartment that is integral with the equipment enclosure or located remotely in an E-house or control room. Whether integrally mounted, or remotely located, NEPSI's control and protection systems are completely tested, set, and calibrated at the factory before shipment.
All stages, whether conventionally or thyristor switched, are protected against short circuit, overload, over-voltage, harmonic over-current, harmonic over-voltage, over-temperature, and unbalance operation from blown capacitor fuses. Protective relays and ancillary protective devices are chosen based on function, cost, reliability, and customer preference.
The Table below summarizes the protection devices that are typically provided with NEPSI’s actiVARTM.
|Short Circuit and
|Provided by the upstream feeder breaker, the main incoming breaker (if provided), or main incoming current limiting fuses (if provided).|
|Over-Voltage||59||Provided to protect the actiVARTM as well as the power system from over-voltage. This system provides backup to the actiVARTM and PFC control which uses voltage as a primary or secondary control input.|
|Under-Voltage||27||Under voltage protection system is provided to disconnect the actiVARTM in the event of a power interruption as well as to detect an actiVARTM control malfunction.|
(Blown Fuse Detection)
|59N or 51N or
51G or Direct
|Relay or direct fuse sensing to detect a capacitor fuse operation. This protection is critical as a blown fuse condition will result in filter de-tuning, lower var output, lower performance, and possible system resonance.|
|Harmonic Voltage &
|Ithd, Vthd||Protection against harmonic resonance, high voltage & current distortion, and harmonic overload.|
|Over-Temperature||26||Over-temperature protection for the thyristor valves, capacitors, and iron-core reactors. Also protects agains fan failure.|
|Over-Load||49||Over-load protection of the harmonic filter, high-pass resistors (if provided), iron-core reactors, and thyristor valves. The overload relay is sensitive to RMS current associated with the filter's fundamental current and harmonic current.|
|Arc Flash Protection||--||ABB UFES System; arc flash protection relay and ultra fast earthing switch to eliminate arcing faults in less than 4 mS. See NEPSI’s arc flash mitigation document for further details on arc flash mitigation.|
The drawing below shows a typical relay protection diagram for an actiVARTM with conventionally switched filter stages. The "actiVARTM" control and the "TSC" stages provide "fast" vars for voltage sag and voltage flicker mitigation. The "PFC" control and "PFC" stages provide "slow" vars for power factor correction, harmonic filtering, and general var support.
NEPSI's actiVARTM is furnished with a fully integrated control and protection system. The controller dynamically controls system voltage by gating the filter stage valves in response to measured power system parameters at a rate of 3 times per cycle. Additionally the controller controls conventionally switched harmonic filter stages with response times of 30 seconds to a minute to control power factor and mitigate harmonics.
The control system consist of a thyristor switch stage controller, key interlock system, HMI, conventionally switched stage controller, and other metering, control, communication, and indication devices that are necessary for the safe, proper operation, and monitoring of the entire system.
|Thyristor switched stage control for dynamic voltage control|
|Conventionally switched stage control for power factor control and harmonic mitigation|
|Fully integrated HMI display|
|Integrally mounted or remotely located control panel|
|Remote access to all controller functions|
CONVENTIONALLY SWITCHED STAGE CONTROL OPTIONS
|Power Factor Control|
|Harmonic Voltage / Current Distortion Control|
|Remote / SCADA Control|
|actiVARTM Product Literature|
|Iron Core Filter Reactors|
|High Pass Filter Resistors|
GUIDE FORM SPECIFICATIONS
|Harmonic Filter and Capacitor Bank Application Studies Spec.|
|actiVARTM - With Power Factor Correction|
|actiVARTM - Without Power Factor Correction|
RELATED PRODUCTS AND SERVICES
|Startup and Commissioning Field Service Rates|
|Power System Studies|
|Metal-Enclosed Power Capacitor Banks|
|Metal-Enclosed Harmonic Filter Banks|
|Hybrid Shunt Reactor and Shunt Power Capacitor Banks|
We encourage you to begin the purchasing process with our online Request For Quote Form. This form is a simple, fast, and convenient way to choose from all the listed options and also provides NEPSI with a good idea of your application requirements.
The options available on the following form are directly related to those listed on this webpage. These two tools should be used together to make your purchasing process much easier.