35kV Top-Mounted Busbar System
This diagram illustrates a top-mounted busbar system assembled from 35kV fully shielded separable cable connectors. It represents a typical application for multi-circuit cable connections in 35kV European-style ring main units (RMUs), compact substations, and other power distribution equipment.
System Overview
The 35kV top busbar system is formed by interconnecting multiple sets of 35kV European-style cable front connectors and rear connectors in series via standardized interfaces, creating a continuous, fully insulated busbar channel capable of simultaneously connecting multiple outgoing feeder circuits. It replaces conventional bare copper busbar systems, achieving fully insulated, fully sealed, and touch-safe busbars within distribution equipment, significantly enhancing operational safety and reliability. The system is purpose-designed for 35kV medium-voltage power distribution.
System Configuration and Operating Principle
Core Components
35kV European-Style Front/Rear Connectors: Manufactured by integral injection molding using ethylene propylene diene monomer (EPDM) rubber, with built-in semi-conductive shielding layers and IP67 ingress protection rating. These connectors serve as the fundamental units of the busbar system and are rated for the 35kV voltage class.
Connecting Busbar: Multiple connectors are connected in series via plug-in interfaces between adjacent connectors, forming a continuous conductive path for current transmission and distribution.
Grounding Assembly: The grounding leads connected to the underside of the connectors (as shown) ground the semi-conductive layer on the connector surface, placing the connector housing at ground potential to achieve touch-safe operation and ensure personnel safety during operation and maintenance.
Operating Principle
Electrical Connection: Cable conductors are electrically connected through the internal conductive components of the connectors. Current is transmitted along the series-connected connector channel, enabling parallel power supply across multiple circuits.
Electric Field Control: The built-in semi-conductive shielding layer within each connector uniformly distributes the electric field, preventing partial discharge caused by electric field concentration under 35kV high voltage and ensuring insulation integrity.
Protection and Safety: The fully sealed structure prevents ingress of moisture and dust. The IP67 protection rating allows operation in harsh environments including high-humidity and heavily contaminated conditions. With the connector housing grounded, there is no risk of electric shock to maintenance personnel upon contact.
System Characteristics and Advantages
| Characteristic | Description of Advantage |
|---|---|
| Fully Insulated and Fully Sealed | No exposed live parts; touch-safe after housing is grounded, completely eliminating electric shock hazard; IP67 protection rating — moisture-proof, dust-proof, and corrosion-resistant |
| Modular Design | Standardized connector units allow flexible expansion based on circuit quantity; convenient installation with no on-site casting or welding required |
| High Reliability | Integral injection molding process with no seams or voids; no aging or cracking risk during long-term operation; service life exceeding 20 years |
| Safe Operation and Maintenance | Grounded connector housing allows direct contact by maintenance personnel; no exposed busbars, eliminating short-circuit faults caused by small animals or foreign objects |
| Space Optimization | Compact structure with minimal footprint; compatible with the confined internal spaces of 35kV ring main units and compact substations |
Typical Application Scenarios
Internal Busbars in 35kV European-Style Ring Main Units: Replaces conventional copper busbar systems to achieve fully insulated connections for multi-circuit outgoing feeders; widely used in 35kV ring main units.
Busbar Systems in 35kV Compact Substations: Provides multi-circuit connections on the high-voltage side within compact substations; compatible with the harsh operating environments of both indoor and outdoor compact substation installations.
Busbars in 35kV Cable Branch Boxes: Enables multi-circuit tapping within cable branch boxes to achieve parallel power supply across multiple cables, eliminating the need for additional busbar support structures.
Distribution Systems in Industrial and Mining Enterprises: Provides busbar connections for 35kV distribution equipment in humid, heavily contaminated, or corrosive environments, improving the system’s resistance to contamination and corrosion.
Installation and Maintenance Guidelines
Installation
Strip the 35kV cable in accordance with specified process requirements, ensuring that stripping lengths and dimensions conform to connector specifications to avoid damage to cable insulation.
Clean the interfaces prior to connector installation, apply silicone grease evenly, and ensure the connector is fully engaged with no looseness or misalignment.
Grounding leads must be reliably connected to ground to ensure the connector housing is at ground potential, thereby achieving touch-safe operation.
Upon completion of installation, inspect all connector sealing surfaces to confirm no gaps or damage, ensuring the IP67 protection rating is maintained.
Maintenance
Periodically inspect the external condition of connectors; verify there are no cracks, damage, discharge marks, or contamination accumulation, and that all connections are secure with no looseness.
Periodically test connector insulation resistance and contact resistance to verify performance compliance and identify potential faults at an early stage.
Clean connector surfaces to remove accumulated dust and contaminants; prevent grease, oil, and chemical substances from corroding the rubber housing.
If abnormalities such as cracks, damage, discharge, or insulation resistance exceeding acceptable limits are detected, the affected connectors must be replaced promptly. Operation with defective connectors is strictly prohibited.
Applicable Standards and Certifications
International Standard: IEC 60840, Test Methods and Requirements for Power Cables with Extruded Insulation and Their Accessories for Rated Voltages above 30 kV (Um = 36 kV) up to 150 kV (Um = 170 kV)
National Standards: GB/T 12706, Power Cables with Extruded Insulation and Their Accessories for Rated Voltages from 1 kV (Um = 1.2 kV) up to 35 kV (Um = 40.5 kV); GB/T 11022, Common Specifications for High-Voltage Switchgear and Controlgear Standards
All system components have undergone type testing at the National Quality Supervision and Inspection Center for Wires and Cables and comply with national electric power industry standards.
Appendix: Product Dimensional Reference Drawing
