The Most Trusted Name in Power Factor Correction and Harmonic Filtering

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Reactive Power Solutions for the Solar Industry

NEPSI offers a full suite of products to meet your reactive power requirements.

Photovoltaic Power (PV) Plants require reactive compensation systems for grid code compliance. Their performance and reactive power ratings are determined by generation interconnection studies, which form the basis for systems to be purchased by the PV developer or EPC. These systems typically include switched shunt reactors and shunt power capacitor banks, and static synchronous compensators (STATCOMs). They are connected to the PV Plant’s collector bus, which is typically at the at the 34.5kV voltage level in North America and 33kV in other parts of the world.

NEPSI provides the PV Industry with packaged solutions, including single-stage and multi-stage metal-enclosed shunt power capacitor banks, harmonic filter banks, single-stage and multi-stage oil-immersed shunt reactors, and hybrid-shunt power capacitor and shunt reactor banks.

NEPSI’s reactive compensation systems come with all switching, all protection, and all controls. The EPC and PV Plant developer can rely on NEPSI to design, build, and deliver a reactive compensation system that costs less, requires a smaller footprint, and offers lower risk.

NEPSI's innovative technologies offered us many different solutions to address the concerns that arose during the development of our project. We were glad to implement a NEPSI product in to our solar environment.

- Recurrent Energy

Industry Concern NEPSI Solution
Sun: UV Light, Radiation Heating
  1. Non-chalking, high gloss retention UV resistant paint
  2. White enclosure
  3. Sun shields
High Temperatures
  1. High temperature designs to 50°C
  2. High temperature fans
  3. Unitized air conditioners
  1. "Filter-Ready" designs that offer low upfront cost
High Activity Seismic Zones
  1. Certified designs to "Zone 4" rating
Wind: Blowing Sand, Dust
  1. Filtered equipment to ensure air integrity throughout
Lead Time
  1. Short project completion times

"Filter-Ready" Capacitor Banks

Always consider the "filter-ready" option for all of your capacitor bank purchases.

Columbia III - Solar / Wind Hybrid Power Plant with NEPSI Capacitor Bank

Harmonic resonant studies conducted on PV power plants often conclude a “possible” need for harmonic filters or capacitor bank detuning, but do not definitively state whether they are required. The studies often recommend harmonic measurements be taken during PV plant commissioning; a recommendation of wait-and-see. Such a recommendation leaves EPC’s in a quandary as grid code compliance requires reactive compensation during commissioning.

NEPSI solves this with their “filter-ready” capacitor banks: a capacitor bank that is equipped with provisions for easy conversion to a harmonic filter bank. Such provisions provide EPC’s with a low cost, low risk solution.

Alternative Switching Technology

Suitable switching devices for switching shunt power capacitor banks and shunt reactor banks at 34.5kV are limited in availability.

For capacitor switches, the renewables industry has standardized on SF6 switches using pre-insertion resistor technology offered by Southern States in a switch carrying the brand name CapSwitcher™. For reactor switching, an RLSwitcher™ is used. Both of these switches are available in NEPSI’s equipment, coming pre-installed, connected, and ready for operation.

NEPSI also offers other alternatives. We replicate the pre-insertion resistor technology with two indoor 40.5kV SF6 circuit breakers from ABB. We use this same 40.5 kV breaker with an RC Snubber for shunt reactor switching. Advantages of these alternatives include:

  1. Low cost
  2. Large service and support network (ABB Service Group)
  3. Short lead-times
  4. Draw-out option for quick swap
  5. Fault interruption capability

C-High-Pass, High-Pass, and Notch Harmonic Filters

PV Power Plants generally have a low level of harmonics and as such do not typically require harmonic filtering to meet harmonic distortion limits. However, with the application of shunt power capacitor banks to meet grid code requirements, even low levels of harmonics can cause significant voltage/current distortion due to parallel resonance. In such cases C-High Pass Filters, Notch Filters, and Harmonic Filters designed and manufactured by NEPSI are employed to de-tune the capacitor bank (Notch Filters) or dampen resonance concerns (C-High-Pass or Standard High-Pass Filter).

Timely Solutions

NEPSI's metal-enclosed banks not only gave us the most cost effective technology available, but also provided us with a solution that is more serviceable in practice. The best part was that we didn't have to wait long either! If you need your equipment fast, be sure to specify the metal-enclosed option.

- Sun Edison

Interconnect studies and shifting reactive power requirements often leave reactive compensation systems as one of the last items to be engineered and procured within a renewable substation. Metal-enclosed reactive compensation systems are sweeping through the industry; they are faster to engineer, procure, and install.

From engineering & procurement to startup & commissioning, NEPSI’s pre-packaged solutions commission 60% sooner when compared to open rack systems.

Typical Product Mix

Voltage Rating: 38 kV
Withstand Voltage: 150 kV BIL, 80 kV 1-Min.
Reactive Power Rating: 2 MVAR to 60 MVAR
Number of Stages: 1 Stage to 6 Stages
Stage Ratings: 2 MVAR to 15 MVAR
Control: Local | Remote, by STATCOM or Grid Controller

Applicable Solutions

Metal-Enclosed Power Capacitor Banks | Web Page
Metal-Enclosed Power Capacitor Banks | PDF File

Metal-Enclosed Harmonic Filter Banks | Web Page
Metal-Enclosed Harmonic Filter Banks | PDF File

RC Snubbers | Web Page
RC Snubbers | PDF File

Hybrid Shunt Reactor & Capacitor Compensation Systems | PDF File

Applicable Specifications

Capacitor Banks - Solar Application Spec. | MS Word
Capacitor Banks - Solar Application Spec. | PDF File

Harmonic Filter Banks - Solar Application Spec. | MS Word
Harmonic Filter Banks - Solar Application Spec. | PDF File

RC Snubber - Guide Form Spec. | MS Word
RC Snubber - Guide Form Spec. | PDF File

Resources of Interest

The Metal-Enclosed Advantage | PDF File
Power capacitor banks and harmonic filter banks can be specified and purchased in two different configurations: “Open-Rack” or “Metal-Enclosed”. This technical note presents background information on these configuration options and provides compelling reasons why the metal-enclosed configuration is a better choice.

An Alternative To Neutral Unbalance Protection | PDF File
This technical note presents an alternate blown fuse detection scheme that utilizes direct fuse sensing. It cost less and provides better protection when compared to neutral-voltage and neutral current unbalance protection.

Harmonic Filter Design | MS Excel
Spreadsheet tool for calculating harmonic filter parameters. Filter types include: C-High-Pass (damped), Standard High-Pass, and Notch Tuned (Delta and Wye Connected) filters.

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