Created by: Glen Zhu | Updated Date: December 29th, 2023
Pipeline transport is vital in modern society, facilitating resource and information flow. Oil and gas pipelines secure energy supply, while water and sewage pipelines sustain urban environments. They have been no less important than any facilities in sustaining normal industrial productivity and residential living.
However, the intricate network of connections and unique attributes of the conveying medium render pipelines exceptionally susceptible to corrosion and lightning strikes when not adequately protected. Implementing the correct lightning protection measures is essential to mitigate risks and ensure the integrity and longevity of the pipeline infrastructure, especially for those carrying risky gas and liquids.
Figure 1 – 3D model of underground piping system nearing electric railways
Industry standards serve as essential roadmaps for implementing effective surge protection in pipelines. The guidelines, established by respected organizations like the National Fire Protection Association (NFPA), the Institute of Electrical and Electronics Engineers (IEEE), provide best practices for safeguarding pipeline systems from the destructive forces of electrical surges.
API RP 1176 offers detailed insights into safeguarding aboveground storage tanks from lightning strikes, a prevalent source of electrical surges in pipeline systems. This standard equips operators with knowledge on effective measures to prevent surge-related damage.
NFPA 77, another significant standard, delves into the intricacies of installing comprehensive lightning protection systems for industrial facilities, including pipelines. It outlines specific requirements and recommendations for lightning protection, ensuring a thorough defense against lightning-induced surges.
IEEE Std 1284, considered a cornerstone of electrical safety, is instrumental in preventing surges from infiltrating and damaging pipelines. This standard provides explicit guidance on proper grounding and bonding techniques, establishing a robust foundation for the electrical integrity and longevity of the pipeline infrastructure.
Adhering to these standards is integral to creating a comprehensive and effective protective framework, assuring the resilience of pipelines in the face of complex environmental and electrical challenges.
Utilizing advanced corrosion-resistant materials in pipeline construction enhances the overall durability and resistance to corrosion, minimizing the risk of structural degradation over time.
Comprehensive training programs for personnel involved in pipeline operation and maintenance are also crucial. Ensuring that staff members are well-versed in recognizing and responding to potential surge-related issues contributes to a proactive approach in protecting the pipeline infrastructure.
In protecting pipelines from lightning and surges, a thorough risk assessment is the cornerstone of any effective strategy. This meticulous analysis digs deep into various critical factors, starting with the pipeline’s location.
Areas prone to frequent lightning storms need extra security, so understanding regional risks is crucial. Historical data on lightning strikes in the area provides valuable insights into the localized threats.
Moreover, the assessment extends to the specific characteristics of the conveying medium and the materials used in pipeline construction. Variations in these factors significantly influence vulnerability to lightning-induced surges.
Potential risk factors:
Large crowds in the vicinity of pipelines necessitate special attention due to the potential for heightened consequences in case of a lightning-induced surge. Ensuring the safety of densely populated areas surrounding pipelines becomes a paramount concern, requiring tailored protective measures to minimize the risk to human life and property.
Pipelines facilitating the continuity of critical services, such as those supporting emergency response systems or essential utilities, merit special consideration. The uninterrupted operation of these services is vital, making the protection of pipeline infrastructure imperative to maintain the functionality of critical systems.
Areas characterized by high lightning flash density pose an elevated risk to pipelines. The increased frequency of lightning strikes heightens the likelihood of surges, necessitating more robust protective measures to mitigate potential damage to the pipeline and associated facilities.
Pipelines situated near tall isolated structures, such as communication towers or industrial chimneys, face an augmented risk. These structures may attract lightning strikes, increasing the potential for induced surges in the pipeline. Targeted protection is essential to safeguard against the unique challenges posed by proximity to such structures.
Pipelines running near buildings containing explosive or flammable materials introduce a specific risk profile. Lightning-induced surges in these areas could have severe consequences, making it imperative to implement protective measures that account for the potential for ignition or explosion.
Buildings housing irreplaceable cultural heritage near pipelines demand special consideration. Lightning-induced surges can pose a threat to valuable artifacts and structures, necessitating protective measures that balance the preservation of cultural heritage with the safety of the pipeline infrastructure.
Electromagnetic interference (EMI) in pipelines refers to the unwanted and disruptive effects caused by electromagnetic fields on the proper functioning of pipeline infrastructure.
EMI can adversely affect the accurate operation of instrumentation and control systems associated with pipeline infrastructure.
In certain cases, EMI can exacerbate the corrosion risk for pipelines. Electromagnetic fields can influence the electrochemical processes on the pipeline surface, potentially accelerating corrosion.
Potential Causes of EMI:
Electric railways generate strong electromagnetic fields that can couple onto nearby pipelines, inducing unwanted currents. These currents can accelerate corrosion, disrupt control systems, and even create sparks in flammable environments.
Figure 2 – Electric railways
High-voltage power lines produce electric fields that can capacitively couple with pipelines, leading to similar effects as electric railways. Extra currents can disrupt pipeline operations, interfere with communication systems, and increase the risk of corrosion.
Figure 3 – Elevated voltage power lines
Faulty equipment or accidental contact with power lines can cause leakage currents to flow through the ground and onto pipelines. Especially the DC currents, can accelerate a specific type of corrosion and disrupt cathodic protection systems designed to prevent corrosion.
Figure 4 – Ground faults
Direct lightning strikes or nearby strikes can induce powerful surges of current into pipelines through conductive coupling or ground currents, which can damage pipeline equipment, ignite flammable materials, and disrupt control systems, potentially leading to operational disruptions and safety hazards.
Figure 5 – Lightning strikes
Grounding system is the top priority of pipeline lightning protection, it is the premise of all protection measures.
The grounding system’s primary function is to capture stray currents from lightning strikes before they reach the pipeline itself. Once trapped, the energy needs a safe pathway to dissipate harmlessly. This is where the equipotential bonding network comes in. The network of interconnected conductors provides a low-resistance path for the captured currents to flow from the electrodes (the “magnets”) to all connected equipment and structures.
Building an effective grounding system requires meticulous attention to detail. The materials used, such as copper-clad steel or stainless steel, must be resistant to corrosion and capable of handling high discharge currents. Every step of the installation process, from the precise placement of electrodes to the careful bonding of connections, must adhere to strict industry standards to ensure optimal performance.
Figure 6 – Earthing diagram for piping systems
Coupling refers to the transmission of electrical energy either between different circuits or within different sections of a circuit. It can occur intentionally as a functional aspect of the circuit, or it may be undesired.
Within the pipeline infrastructures, the intricacies of electrical engineering and corrosion protection necessitate a nuanced approach to grounding. That is to Avoid connecting the earth electrode directly to the pipeline, as doing so would compromise the effectiveness of the cathodic corrosion protection measure.
Corrosion poses a perpetual threat to pipelines, and as a proactive measure, they are often charged with a protective current. This cathodic corrosion protection involves the intentional induction of a direct current (DC) that counteracts the corrosive processes attempting to degrade the pipeline’s structural integrity. However, the delicate balance lies in maintaining the effectiveness of this protective current while avoiding unintended consequences that could exacerbate corrosion issues.
Connecting the earth electrode directly to the pipeline might seem intuitive at first glance, as both are integral components of the grounding system. However, doing so would create an unintended pathway for the protective current to discharge directly into the earth. The direct connection could inadvertently disrupt the cathodic corrosion protection measure, diminishing its effectiveness in mitigating corrosion.
To circumvent this challenge, the installation of a decoupling device assumes paramount importance. Positioned strategically between the pipeline and the earth electrode, the decoupling device selectively allows the protective DC current to flow through, ensuring that the cathodic corrosion protection measure remains intact. Simultaneously, the decoupling device efficiently discharges all harmful alternating current and impulse currents via the earth electrode, preventing unwanted currents from interfering with the pipeline’s protective mechanisms.
Decoupling devices can be mounted in three ways, and the diagrams are shown as follows:
Figure 7 – Decoupling devices flush mounted
Figure 8 – Decoupling devices pole mounted
Figure 9 – Decoupling devices wall mounted
Insulating joints and flanges are essential in the domain of lightning and surge protection for pipeline systems. When it’s needed, the system shields infrastructure from potentially damaging forces associated with high voltages and electrical surges, especially crucial when segmenting pipelines into distinct sections in regions susceptible to elevated voltages.
The components serve a fundamental purpose—establishing galvanic isolation within cathodic corrosion-protected pipeline system, which helps prevent the undesired flow of electric currents to the system earth. The isolation is critical in averting adverse effects like open sparking, leakages, or the potential destruction of insulating joints. Without adequate installations, Potential risks would arise when exposed to extreme voltages induced by lightning strikes or short circuit currents from nearby casing sources.
Strengthening resilience against lightning-induced surges involves incorporating ex isolating spark gaps as a protective measure. The spark gaps could discharge energy in a controlled, non-sparking manner, particularly vital in environments where explosive conditions may exist. The facilities enhance the overall protective capabilities of the pipeline system.
The proper installation and regular maintenance of insulating joints, flanges, and associated lightning protection mechanisms are paramount. Incorrect installation or neglecting routine maintenance can compromise insulation effectiveness, potentially exposing vulnerabilities in the pipeline system. As integral components of a comprehensive lightning and surge protection strategy, these elements significantly contribute to the overall resilience of pipelines, mitigating risks and ensuring the reliable and safe operation of the infrastructure.
In scenarios where high voltages are a concern—such as when segmenting pipelines into individual sections—insulating joints and flanges is critical by establishing electric (galvanic) isolation within cathodic corrosion-protected pipeline systems, acting as a barrier to system earth.
Opting to install the ex-isolating spark gap coaxial connection box outside hazardous areas brings several advantages. Placing the spark gap aboveground allows for the use of longer cables, simplifying maintenance and inspections. The external configuration eliminates the need for frequent excavation, streamlining testing procedures and reducing operational disruptions.
Importantly, inspections can be conducted efficiently without requiring approval from the operator, and no special protective clothing or test equipment is necessary. The external installation of the coaxial connection box enhances operational efficiency and offers cost-effective testing directly on the box, contributing to the overall effectiveness of lightning and surge protection measures for pipelines.
Figure 10 – Lighting and surge protection system diagram of pipeline networks
In impressed current cathodic protection, a mains-powered rectifier is indispensable for generating the required protective current, directed into the protected object, like a buried pipeline, through impressed current anodes in the ground. Modern rectifiers surpass basic power supply; they integrate control devices assessing the pipeline’s protection potential against a reference electrode. The devices can autonomously adjust the cathodic protective current for optimal corrosion prevention. Installing cathodic protection on pipelines can greatly minimize the risk of leaks and failures.
A complete cathodic corrosion protection system includes key elements: cathodic protection rectifiers delivering the protective current, control devices with a reference electrode, and impressed current anodes.
However, directly connecting the cathodic protection rectifier to the pipeline, anodes, system earth, and reference electrode poses risks. The direct galvanic connection can cause over-voltages, which could result in disrupting and destroying devices and increasing the fire risk.
To address the challenges, using protection concepts specifically for safeguarding cathodic protection rectifiers is significant. The reliable equipment effectively manage various forms of overvoltage, including transient overvoltage from lightning effects and switching operations, and temporary overvoltage from short-circuits related to traction current and high-voltage systems.
Figure 11 – Wiring diagram for currents up to 12 A
Figure 12 – Wiring diagram for currents greater than 12 A
Surge protective devices could be the most effective protective equipment that exits in the market globally. The selection and placement of surge protective devices (SPDs) in a pipeline system depend on the specific vulnerabilities and potential sources of transient over-voltages. Surge protection systems are more needed in water pipelines as they experience a greater risk of short circuits.
FLP25-275/3+1 is installed at the main electrical panels of facilities associated with the pipeline for TT and TN-S systems, whether it’s a water treatment plant, a gas compressor station, or a facility handling other substances.
It provides with primary protection against direct lightning strikes.
In areas nearing pumping stations and compressor units and junction points of branching, type 1+2 surge arresters are greatly needed to protect against surges generated by the starting and stopping of large motors or other inductive loads.
Type 2 SPDs, for example, SLP40-275/3S+1 can be placed at sub-distribution panels within the various facilities along the pipelines protecting downstream equipment from surges generated within the electrical distribution system.
Data surge arresters FRD2 series are essential within circuits across information transmission of the piping systems, including control panels, communication equipment, and other data lines associated with the transportation and monitoring of substances through the pipeline.
EX isolating spark gap with connecting cables for aboveground and underground installation; with water-proof sheath; may be shortened
for short cable lengths.
Application: Indirect by-passing of insulating flanges and insulating glands.
Lightning Equipment Bonding – Isolating Spark Gap TYP 480
Lightning Equipment Bonding – Isolating Spark Gap TYP 481
lsolating spark gaps with plastic coating and two stainless steel connections (Rd 12 mm).
LSP’s reliable surge protection devices (SPDs) are designed to meet the protection needs of installations against lightning and surges. Contact our Experts!
Copyright © 2010-2024 Wenzhou Arrester Electric Co., Ltd. All Rights Reserved. Privacy Policy
