Electric Transmission
DEI has extensive experience with high-voltage transmission system protection. Our products are used for safety grounding on pipe-type cable and lead sheath cable construction, replacing older technologies. DEI products allow copper concentric neutrals or sheaths to be galvanically isolated from lead sheath construction. Pipe-type cable with insulated joints in oil supply lines can be protected from AC faults and lightning. Power transformers can be protected from GIC and DC currents in the neutral grounding conductor using DEI decoupling devices. Assured safety grounding and greater reliability are the hallmarks of an electric transmission grid protected by DEI products.
Electric Distribution
DEI’s initial solid-state product was for electric distribution use where objectionable neutral-to-earth voltage affected farm customers. The Neutral Isolator (now the Variable Threshold Neutral Isolator) allowed primary-to-secondary isolation to address this issue. An interesting offshoot of this application appeared when a utility client wanted only DC isolation from the primary grounding system due to the effects on their cathodic protection system. This “decoupling” of the utility and customer grounds leaves the AC system unaffected and provides only DC isolation, in a fault-rated product.
Gas/Oil/Products Pipelines
DEI offers many solid-state products and solutions to the pipeline industry. Insulated joint protection schemes can benefit from our products certified for hazardous location use. Induced AC voltage mitigation has never been easier with our solid-state devices, which replace older technologies. New applications are possible only because of DEI’s solid-state technology and independent product listings. Motors or other electrical equipment on the pipeline cathodic protection can be decoupled from the copper grounding system, and comply with electrical codes. Likewise, an entire station or facility can be decoupled from the electric utility grounding system for improved cathodic protection system performance.
Water Pipelines
Some applications on water pipelines are possible only because of DEI’s solid-state technology and independent product listings. Where motors or other electrical equipment on the pipeline cathodic protection are bonded to the copper grounding system, cathodic protection will be affected. Normal procedures call for insulated joints to be installed on either side of the motor operated valve, but costs on very large diameter pipe can approach $1,000,000 for an installed system. Why not forget the joints, spend under $4,000, and increase your system reliability at the same time?
Likewise, an entire station or facility can be decoupled from the electric utility grounding system for improved cathodic protection system performance. Insulated joint protection schemes can benefit from our products certified for hazardous location use. Induced AC voltage mitigation has never been easier with our solid-state devices, which replace older technologies.
Tank Farms / Terminals
Sites with tanks and underground piping have numerous applications involving DC isolation and AC grounding. Often tank farms and terminals have insulated joints separating transportation piping from the facility. Such piping may be subject to induced AC voltage due to overhead power lines, which can appear at the insulated joint at the facility perimeter. Both over-voltage problems can be addressed by DEI products.
Often, tanks or piping have grounded electrical equipment, such as motors, mounted on them, which affects the cathodic protection. As compared to using insulated joints or fittings to solve this problem, DEI offers third-party listed (certified) decouplers that meet electrical codes and block CP current. The products can also be used to separate one tank CP system from another.
If the above situation is of interest, but the site has too many bonds to the grounding system, then a simpler solution is to isolate the entire facility from the power company grounding grid.
As most tank farms and terminals are classified (hazardous) locations, DEI offers products listed for use in Div 1, Div 2, and Zone 2 areas.
Refineries / Plants
Refineries and plant settings often have a complicated collection of cathodically protected pipelines, tanks, and other structures. Even so, such protected infrastructure can be separated from grounding systems or unprotected structures using DEI products.
Refineries and plants usually have insulated joints separating transportation piping from the facility, which are subject to over-voltage conditions. Such piping may also be subject to induced AC voltage due to overhead power lines, which can appear at the insulated joint at the facility perimeter. Both over-voltage problems can be addressed by DEI products.
Often tanks or piping have grounded electrical equipment, such as motors, mounted on them, which affects the cathodic protection. As compared to using insulated joints or fittings to solve this problem, DEI offers third-party listed (certified) decouplers that meet electrical codes and block CP current. The products can also be used to separate one tank CP system from another.
If the above situation is of interest, but the site has too many bonds to the grounding system, then a simpler solution is to isolate the entire facility from other grounding grids or the power company grounding system. Since it is common to have classified (hazardous) locations in refineries and plants, DEI offers products listed for use in Div 1, Div 2, and Zone 2 areas.
Airports
Airport fueling systems utilize cathodic protection on jet fuel piping, which requires isolation from ground in order to have adequate protection. Isolation is accomplished through insulated joints and coatings, and DEI specializes in providing over-voltage protection for these systems. The Army Corp of Engineers specifies the DEI model OVP for military facilities that need insulated joint protection. At either above-grade insulated joints or those in hydrant pits, the OVP is rated and third-party listed (certified) for hazardous location use.
Fueling systems also utilize motorized pumps and valves that can compromise the cathodic protection because of the required electrical grounding conductor. DEI solves this problem through the use of a third-party listed decoupler that can be placed in series in the ground, and eliminates the need for insulating joints on either side of the grounded electrical equipment. The device is also listed for hazardous location use. This same application addresses cathodically protected tanks that require decoupling from the site grounding grid in order to achieve adequate cathodic protection levels.
Rail Systems
Rail corridors are attractive areas for placement of other utility services, such as electric transmission lines or gas pipelines. The result can be that rail currents affect nearby structures, or the rail system is affected by electric transmission lines. DC rail current can greatly affect pipeline cathodic protection systems, and both can be impacted by induced AC 60Hz voltage and current from overhead electric transmission lines. Complicating matters further, the rail signaling system may operate at several kHz, and any solution must not compromise the correct signaling on the line.
DEI has provided specialized equipment for AC voltage mitigation on rail systems, while leaving the signaling system unaffected. The devices provide steady-state 60Hz mitigation, while blocking DC current and higher frequency signals. Other specialized devices include rail insulated joint protectors for over-voltage protection, which block all signals up to a threshold.
Service Stations
Gasoline service stations utilize cathodically protected underground tanks for storage, and suffer a particular challenge as the result of the required safety grounding of the tanks. With submersible pumps in metallic contact with the tanks, the cathodic protection system is now connected via the submersible pump grounding conductor to the entire utility grounding system. The result is either inadequate cathodic protection readings or interference with the local utility pipelines, such as a gas distribution company. DEI can solve this problem through the use of a solid-state decoupler placed in series in the submersible pump grounding conductor.
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