Graphite-based flexible composite grounding material Flexible Graphite Composite Electrical Grounding Material ) Product Introduction

Graphite-based flexible grounding materials are composite lightning protection and grounding materials that are being actively promoted by State Grid Corporation and China Southern Power Grid Company. Its structure is shown in the figure. It adopts... Litz The structural principle of the wire ensures that the electromagnetic field inside it is distributed relatively uniformly, thereby resulting in a fairly even current distribution across each graphite conductor. For its preparation, high-purity flake graphite (purity: ...) is used. ≥ 95% ), expanded graphite is prepared through pretreatment of graphite, and then combined with inorganic fibers, synthetic fibers, and a water-based conductive adhesive in a specific ratio. The material is fabricated using roll pressing, thermoplastic processing, and twisting processes. Its... The softening process involves modifying graphite—known for its excellent conductivity and corrosion resistance—to enhance its electrical, physicochemical, and mechanical properties, ensuring that it meets the technical requirements for lightning protection grounding systems and engineering construction. It effectively addresses the issues of corrosion and unstable grounding resistance in industrial and civil grounding facilities—including transmission line towers, substations, power plants, communication base stations, railways, port terminals, oil and gas facilities, and buildings—and demonstrates significant advantages over traditional copper and aluminum grounding materials in practical applications.

Graphite-based flexible grounding material Main features

( 1 ) Good electrical conductivity and impact resistance; the measured resistivity is approximately... 3.25 × 10 ^-5 Omega ·m ( Pass through Pass Material material Change Enter Possible Enter One Step fall To 10^-6 Omega ·m Level), The tests show that the grounding electrode and connection points are... 120kA Under the impact of the above-mentioned surge currents, the structure remains stable and can effectively dissipate both lightning currents and short-circuit fault currents.

( 2 ) Stable corrosion resistance. Its corrosion resistance in soil conditions such as acidic, alkaline, and saline environments is significantly superior to that of metallic grounding materials, and when used in conjunction with reducing agents, it does not cause corrosion of the grounding electrode, thereby lowering the total lifecycle cost of the grounding system.

( 3 ) Mechanical structure is stable. Graphite composite grounding material ( Phi 28mm tensile strength of) ≥ 23kN Tensile strength of the connection point ≥ 7kN , meeting the actual grounding construction requirements.

( 4 ) Good thermal stability. The new grounding material exhibits excellent performance at high temperatures ( 200 ℃ test) and low temperature ( -40 The structure remains stable under ℃ testing conditions, and its resistivity exhibits negative temperature characteristics.

( 5 Graphite-composite grounding materials feature flexibility and bendability, allowing for flexible selection of construction methods based on actual terrain conditions and thereby reducing construction costs. The grounding body deforms under the same external forces as the soil, ensuring high conformity with the soil.

( 6 ) Graphite composite grounding materials have low secondary utilization value, effectively preventing man-made theft and sabotage.

( 7 ) The production cost of the material is controllable and offers a cost advantage compared to metal materials such as copper.

Graphite-based flexible grounding material Key Performance Indicators

Graphite-based flexible grounding material in Advantages in engineering applications

1 As a new type of non-metallic grounding material, graphite-composite grounding materials, compared to current metallic grounding materials, ... It features corrosion resistance, low cost, ease of transportation and construction, close adherence to the soil, and anti-theft properties.

2 Compared to metallic grounding materials, graphite-composite grounding materials exhibit a less pronounced skin effect, have higher material utilization, and demonstrate lower inductive effects than steel grounding materials. As a result, the power-frequency grounding resistance of graphite-composite grounding materials is lower than that of steel grounding materials. Under the action of high-frequency lightning currents, the impulse grounding impedance of copper is significantly lower than that of steel.

3 Graphite-composite grounding materials meet the application requirements for grounding works of transmission line towers under harsh geological conditions and thus possess practical application value and promising prospects.

The practicality of graphite-based flexible grounding materials Application

Application 1: Lightning Protection Grounding for Poles and Towers

• Engineering Objective: “Maintain power frequency, reduce impact”
• Construction method: Two-step method,
• 
• 1) Root opening + spark piercing → reduced impact resistance
• 2) Radiation → Reduced power frequency resistance

Application 2: Renovation of Large Grounding Grids at Power Plants

• 1) Renovation goal: Can start from 0.28 W Drop to 0.15 W ；
• 2) Flat steel cannot be used as material for grounding upgrades, as magnetic materials have high inductive reactance.
• 3) Copper rods cannot be used as grounding materials due to electrolytic corrosion.
• 4) Only flexible graphite composite grounding electrodes can effectively complete the renovation task.

Application 3: Resistance Reduction Retrofit for the Communication Dispatch Building

• Available from 3.3 W Drop to 0.5 W  
• The park area is small; if we don't leverage the nearby conditions, we won't be able to succeed.
• River sewage is a good diffusive medium.
• In the river channel, neither copper nor flat steel can be used.

Application 4: Substation Grounding Renovation Plan

• Can be obtained from the existing ground network. 1.2 W Drop to 0.5 W  
• Modifying the traditional methods within the substation cannot meet the requirements for reducing resistance.
• Utilize the green belts outside the site without disrupting the garden landscape.

Application 5: Flexible Graphite-Assisted Anode

• Meet the requirements for anode materials:
  • Good electrical conductivity ( 10 ^-5 W m)
  • Has a stable grounding resistance when in contact with soil or groundwater (flexible braiding, tightly bonded to soil).
  • At high current densities, its surface polarization is relatively small (allowing for higher current densities). 5-10A/m² )
  • Low corrosion rate in harsh environments and excellent chemical stability (inherently corrosion-resistant).
  • Has sufficient mechanical strength ( 1 kN), facilitating construction and installation (crimping).
  • Low price, readily available source (abundant reserves)
  • Good resistance-reducing effect (easy to stretch)
  • Avoid soil metal contamination and reduce emissions.
  • No need to install an anode ground bed.
• Commonly used auxiliary anodes:
  • High-silicon cast iron, graphite, steel
  • Copper-core flexible anode, precious metal oxide