MV da HV Cable Termination zuwa Equipment & Joints

Masuwa da Muhimmanci a Zabe Kable da Turancin Karamin Kirkiro

Idan kana son zabe karamin kirkiro a cikin switchgears na gida, motors masu karamin kirkiro, transformers masu karamin kirkiro, instrument transformers, da sauransu masu karamin kirkiro da karamin kirkiro mafi yawa (MV, inda tushen bayanan karamin kirkiro ta shi shine（1 kV<V<60 kV) da karamin kirkiro mafi yawa (HV, inda V≥60 kV ), yawancin matsaloli sun dace. Wannan matsaloli sun haɗa daga mutane da ke tsari, musamman wadanda ke tsari don switchgears. Don haka, tashar daidaito da wasu mai sarrafa abubuwan da ake amfani da su ya fi kyau ko karfi.

Abubuwa da Duk Da Su Duba a Zabe Kable da Turancin Karamin Kirkiro Cikin Lura zuwa Fafutukar Jirgin Gwiwa

Abubuwa a Zabe Kable da Turancin Karamin Kirkiro

A zabe karamin kirkiro, akwai kamfanon da za su duba don hana aiki da ingantaccen da lafiya da kudin:

• Bus da Supporting Structures: Tsarin, abincin, da kare da busbars da supporting structures su sun muhimmanci. Suna bukata da karamin kirkiro, yanayin yanayi, da kuma kamar karamin kirkiro mafi yawa a lokacin da su maye tsari da kalmomi da kudanci.

• Circuit Breaker Insulation Structure: Tsarin insulation a cikin circuit breakers ya fi kyau don koyar da karamin kirkiro. Ya kamata a iya maye rated voltage, transient overvoltages, da kuma yanayin al'umma ba tana juye ba.

• PD (Partial Discharge) Analysis: Amfani da partial discharge analysis ya taimaka wajen samun alama da suka bari don koyar da insulation. Partial discharges suna nuna nasarorin da suka shafi insulation system, idan ba a yi aiki kan ba, zai iya haifar da kisan karamin kirkiro.

• Insulation Material: Zabin insulation material, musamman oil, sulfur hexafluoride (SF6), ko vacuum, ya taimaka wajen samun aiki. Har abu a nan suna da muhimmancin da kuma batun da ake amfani da su a tsari, arc-quenching capabilities, environmental impact, da kuma muhimmin aiki.

• Wedging System Condition: Wedging system, wanda ke tsari wadanda ke maye, ya kamata a iya maye tsari da kalmomi. Wedging system da ba da tsari ba zai iya haifar da kisan karamin kirkiro, kudin karamin kirkiro, da kuma karamin kirkiro mafi yawa.

• Cooling Gas Type: Idan karamin kirkiro ya dogara da gas-based cooling systems, abin da ake amfani da ita a cooling gas sun taimaka wajen koyar da heat dissipation da kuma aiki da kullum. Abubuwan gas suna da koyar da thermal conductivities da kuma heat-carrying capacities.

• Proximity of Grounded Components to High-Voltage Conductors: Yawancin grounded components da high-voltage conductors su sun muhimmanci. Proximity mafi yawa zai iya haifar da electrical leakage, flashovers, ko interference, don haka, tsarin insulation da kalmomi suna bukata.

Zabe Kable zuwa Fafutukar Jirgin Gwiwa

Zabe kable zuwa fafutukar jirgin gwiwa, wanda ake kira OH/OG terminations, suna taimaka wajen koyar da electrical distribution networks. Waɗannan terminations suna da tsari don systems da rated voltages har zuwa 36 kV. Ayyukan da suke da su sun haɗa daga koyar da karamin kirkiro zuwa pre-assembled indoor ko outdoor switchgears, zuwa koyar da routing da karamin kirkiro a lokacin da ba a yi aiki kan overhead lines zuwa wurare.

OH/OG terminations suna da tsari don oil-paper da cross-linked polyethylene (XLPE) insulated cables, wanda suke da single-core ko three-core. Suna da tsari don a yi aiki a gwargwadon, da suke da metallic structures da suke da tsari don overhead line poles da wood, concrete, ko metal, kamar yadda aka bayyana a Figure 1.

Wannan da ya fi kyau a cikin OH/OG terminations shine cewa metallic structures su suna da tsari don ground. Hakan ya taimaka wajen koyar da electrical shocks, dissipate fault currents, da kuma koyar da electrical safety da kullum.

Tsari da Koyar da OH/OG Metallic Structures da Cable Installations, da Elbow Terminations

OH/OG Metallic Structure and Cable Installation Requirements

Gaskiya ta OH/OG (Overhead/Underground) metallic structure ba ta shi ne, ya kamata a iya maye minimum insulation safety distance zuwa ground kamar yadda an bayyana a standards na industry. Wannan ya taimaka wajen koyar da koyar da electrical system, koyar da electrical hazards kamar accidental contact ko arcing zuwa ground.

Idan kana son sanar da cables zuwa OH/OG terminations, ya kamata a sanar da su a sifa da pole da ya shiga. Wannan ya taimaka wajen koyar da koyar da damage daga vehicles, wanda ke taimaka wajen koyar da reliability da longevity da electrical infrastructure. A cikin process na installation da kuma a lokacin da cables suke da tsari, ya kamata ba a yi bend beyond the manufacturer-specified minimum internal bending radius. Idan ba a yi aiki kan ba, zai iya haifar da internal damage zuwa cable insulation da kuma conductors, wanda ke taimaka wajen koyar da electrical failures. A wasu lokutan, don hana minimum bending radius, ya kamata a sanar da poles mafi yawa, wanda ke taimaka wajen koyar da planning da installation phases. Kuma, OH/OG terminations suna da tsari don animal-proofing measures, wanda ke taimaka wajen koyar da cables daga damage daga animals, wanda ke taimaka wajen koyar da power outages da kuma electrical safety risks.

Elbow Terminations

Cable terminations suna da tsari don koyar da cables zuwa terminals da sauransu masu aiki, musamman transformers, motors, da pre-assembled switchgears. Amma, saboda hanyoyin aikinsu ko nature da equipment terminals, akwai lokutan da cable connection zuwa bushings ya kamata a seal. A wasu lokutan, elbow terminations, kamar yadda aka bayyana a Figure 2, suna da tsari. Waɗannan specialized terminations suna taimaka wajen koyar da secure electrical connection, da kuma sealing functionality, wanda ke taimaka wajen koyar da electrical system daga environmental elements da kuma koyar da aiki da kullum.

Elbow Terminations and Their Application in Ring Main Units (RMUs)

Elbow terminations suna da muhimmanci da tsari, musamman a connecting cables zuwa bushings da Ring Main Units (RMUs). RMUs suna da tsari don compact, self-contained, da fully insulated switchgear systems, wanda suke da sulfur hexafluoride (SF6) da take da tsari don insulation. Suna da tsari don secondary distribution networks, wanda suke taimaka wajen koyar da managing da distributing electrical power a cikin wurin.

Wannan da ya fi kyau a cikin RMUs shine cewa suna da tsari don internal arc withstand, wanda ke taimaka wajen koyar da electrical system. Live parts da RMUs suke da tsari don maintenance-free, wanda ke taimaka wajen koyar da frequency interventions da kuma downtime. Kuma, modular nature suke taimaka wajen koyar da easy expansion a cikin installation site, wanda ke taimaka wajen koyar da system zuwa changing power demands zuwa zamani.

Switching da protection functions a cikin RMUs suna da tsari don switch-disconnectors da fuses ko circuit breakers. Wannan configuration ya taimaka wajen koyar da electrical system zuwa safe isolation, faults zuwa quick detection da clearing, da kuma koyar da integrity da distribution network.

Elbow terminations suna da tsari don connecting cables zuwa RMU bushings, kuma suna da tsari don multiple cables zuwa same bushing da electrical equipment. Kamar yadda aka bayyana a Figure 3, waɗannan terminations sun taimaka wajen koyar da practical da reliable solution zuwa complex cable-to-equipment connections, wanda ke taimaka wajen koyar da efficient distribution da electrical power da kuma koyar da integrity da safety da overall system.

Elastimold Cable Joints & Terminations

Elastimold shine brand da ake sanar da comprehensive range da equipment da accessories zuwa cable splicing da termination, da ake tsari don rated voltages zuwa 36 kV.

Elastimold cable terminations suna da tsari don single-piece da modular designs. Waɗannan versatile models suna da tsari don various applications, musamman transition from underground cables zuwa bare overhead conductors, connections zuwa live-front equipment, da elbow connections, wanda ke taimaka wajen koyar da both indoor da outdoor use. Suna da tsari don seamless integration into oil, SF6, da air-insulated high-voltage switchgear, da kuma transformers, motors, da capacitors.

Designs da Elastimold products suna da advanced silicone rubber insulating materials. Waɗannan materials sun taimaka wajen koyar da creep, electrical strikes, weathering, da contamination, wanda ke taimaka wajen koyar da reliable performance even in the harshest conditions. Compact da lightweight nature da Elastimold units sun taimaka wajen koyar da easy installation in confined spaces da kuma free-hanging applications.

Elastimold devices suna da ATEX-certification. ATEX, derived from the French title of the 94/9/EC (European Commission) directive "Appareils destinés à être utilisés en ATmosphères Explosibles" (Equipment to be installed in explosive atmospheres), these high-voltage bushings are suitable for use within oil or air-insulated switchgear and transformers in hazardous areas, such as those found in the oil, gas, and petrochemical industries. The manufacturing of Elastimold equipment adheres to international standards set by IEC (International Electrotechnical Commission), ANSI/IEEE (American National Standards Institute/Institute of Electrical and Electronics Engineers), and CENELEC (European Committee for Electrotechnical Standardization).

Elastimold offers several specialized devices for specific applications:

• Separable Elbow Connectors and Accessories: These are load-break connectors that provide a convenient means of connecting and disconnecting cables and equipment in power distribution systems. Load-break elbows are designed for energized operation using standard hot-stick tools, enabling load make/break operations and providing a visible disconnect. The components can be isolated using insulated caps, plugs, and parking bushings.

• Metal Oxide Varistor (MOV) Surge Arresters: These arresters are fully shielded and fully-submersible, designed for overvoltage protection. They feature 200 A separable connector interfaces for easy attachment to other Elastimold accessories. Elastimold arresters offer high-voltage protection against lightning and switching surges for transformers, cables, equipment, and other components typically found in underground power distribution systems. Proper placement, voltage selection, and coordination with riser pole arresters can significantly enhance protective margins and minimize damaging surge voltages. Typical applications include installing arresters at the end of a radial system or at both ends of an open point on a loop system, with additional arresters added at strategic upstream locations for optimal protection.

• Fused Elbows: These combine replaceable current-limiting fuses for current protection in OH/OG cable terminations with 200 A separable connector interfaces for compatibility with other Elastimold accessories.

Raychem is another commonly recognized brand in the field of cable splicing and termination equipment.

Terminations for GIS (Gas Insulated Substations)

When the available space for substation installation is limited or environmental conditions are extremely harsh, a Gas Insulated Substation (GIS) is often the preferred solution. GIS is a compact, multi-component assembly housed within a grounded metallic enclosure. It contains bus bars, circuit breakers, isolators, and instrument transformers, with compressed sulfur hexafluoride (SF6) gas serving as the primary insulation medium, ensuring reliable phase-to-ground insulation. While GIS are typically installed indoors, outdoor models are also available.

GIS units are equipped with cable termination enclosures where cable terminations are installed. According to IEC Standard 60859, both the enclosures and cable terminations must meet specific dimension requirements to ensure interchangeability. Cable terminations for GIS are suitable for gas, oil-paper, and XLPE-insulated cables and share many components with the cable joints previously discussed.

Features of GIS Cable Terminations

The main features of GIS cable terminations include:

• Cable Lug: Facilitates the connection between the cable conductor and the termination.

• Box Body: Typically made of aluminium alloy or a similar material, providing structural support and protection.

• Reliable Support Insulator: High-grade, non-tracking epoxy insulators offer excellent mechanical and electrical properties. These insulators are compatible with SF6 gas by-products, ensuring a long service life for the termination. Their design also allows for an optional cable shield break.

• Filling Compound: Such as transformer oil, polybutene oil, or similar substances, which help in insulation and stress relief.

• Stress Control Cone with Bundle Tape: Manages electrical stress at the cable insulation-termination interface.

• Rigid Cable Support: The connector is securely locked in place by a threaded hood at the top of the support insulator. This design ensures that the electrical connection between the GIS and the termination is not subjected to mechanical forces from the cable.

• Positive Sealing System: A double "O" ring sealing system is employed to seal the termination oil compartment from the GIS SF6 compartment. Fully retained gaskets are compressed to prevent the ingress of atmospheric elements into the termination interior.

• Earthing Clamp: Provides a secure connection for earthing purposes.

Figure 4 illustrates a schematic of a GIS cable termination. Some models available on the market do not require the use of oil, eliminating the need for an oil housing.

Sealing, Connection, and Installation Requirements for GIS Cable Terminations

Sealing System

The sealing system of GIS cable terminations is of paramount importance and must be meticulously designed. Its primary function is to prevent the leakage of oil or gas into the GIS. A compromised seal could lead to insulation failures, gas loss, and potential safety hazards. By ensuring a robust and reliable sealing mechanism, the integrity of the GIS environment and the overall electrical system is maintained.

Mating Connection Piece

The GIS supplier is responsible for providing a mating connection piece that is specifically designed to be fitted to the cable end. This component is crucial for establishing a secure and electrical connection between the cable and the GIS. The precise design and compatibility of the mating connection piece are essential to ensure seamless integration and optimal performance of the cable-GIS interface.

Isolation and Testing Facilities

To guarantee the safety and reliability of the electrical system, proper facilities must be provided to safely isolate a feeder cable. This isolation capability is necessary during maintenance, repairs, or fault-finding operations. Additionally, provisions should be made to connect a high-voltage test cable to either the GIS or the cable itself. These testing facilities enable routine inspections and diagnostic tests to assess the condition of the cable and the GIS, helping to identify potential issues before they escalate into major problems.

Required Tools and Accessories for GIS Termination Installation

For the successful installation of GIS cable terminations, a specific set of proper tools and accessories is indispensable:

• Panduit Pliers: These pliers are specifically designed for installing bundle tape around the stress cone. The accurate application of the bundle tape is crucial for managing electrical stress and ensuring the long-term reliability of the termination.

• Circlip Pliers: Used for the installation of the top fitting, circlip pliers provide the necessary grip and precision to secure this important component in place.

• Adapter Flange: The adapter flange plays a key role in facilitating the connection between different components, ensuring a proper fit and alignment within the GIS termination system.

• Top Fitting Removal Kit: This kit is essential for maintenance and repair operations, allowing for the safe and efficient removal of the top fitting when required.

• Re-assembly Kit: The re-assembly kit contains all the necessary components and hardware to put the termination back together after maintenance or repairs, ensuring that all parts are replaced correctly.

• Earthing Kit: An earthing kit is vital for establishing a secure electrical connection to the ground, which is essential for the safety of the electrical system and personnel.

• Screen Connection: The screen connection ensures the proper grounding and shielding of the cable, reducing electromagnetic interference and enhancing the overall performance of the cable-GIS system.