35kv light arrester

Types of 35kv light arresters

Light arresters, also known as lightning surge arresters, play a crucial role in electrical systems where they help to provide system protection by dissipating lightning or switching surges to keep electrical equipment intact. 35kV light arresters are designed for high-voltage systems.

The following are the types of 35kv light arresters:

• Ceramic 35 kv Lightning Arrester

  A ceramic 35kV lightning arrester uses a ceramic housing for its varistor. The varistor is a voltage-dependent, nonlinear resistor used for surge protection. The advantage of a ceramic or porcelain housing is that it is very durable and weather-resistant, which makes it suitable for outdoor use or areas with extreme temperatures. Ceramic varistor lightning arresters are specifically designed to divert surge voltages and protect the electrical equipment from damage within substations, power plants, and industrial facilities.

• Polymer 35 kv Lightning Arrester

  Unlike ceramic arresters, polymer 35kv lightning arresters use a polymer or silicone rubber housing, which makes them lightweight and easier to install in hard-to-reach areas. They are also more resistant to damage from environmental factors such as UV rays, salt spray, and acid rain. These arresters are suited for industrial, marine, coastal, and other environments where extreme weather conditions are common.

• Metal Oxide 35kv Lightning Arrester

  As the name implies, metal oxide arresters are lightning arresters that employ metal oxide varistors (MOVs) as the core of their operation. The MOV provides voltage clamping to absorb transient surges. Ideally, a 35kV metal oxide lightning arrester will have a lot of MOV discs stacked up within the metal housing. The MOVs inside an MOV works by redistributing electrical energy throughout the discs to equalize the electrical energy across the discs and prevent the surge from breaching the threshold voltage. When this happens, the surge will be redirected through the carbonized paths and the MOV will cease to function until the power is restored.

• 35kv Lightning Arrester with Discharge Rods

  This type of lightning protector comes with external discharge rods. These rods help to ionize the air near them, creating a low-resistance pathway for the lightning to follow down into the ground. It not only helps to protect the electrical equipment but is also very effective at protecting transmission lines and structures like wind turbines, cranes, and antennas.

• 35kv Lightning Arrester without Discharge Rods

  A discharge rod is a common feature in most lightning arresters, but not all application-specific lightning arresters need them. For example, in areas where the threat of lightning is moderate or low, or the electrical installation is sheltered, having an internal-only arrester with no external rod is more convenient because it has less installation complexity and is lighter. Still, for high voltage environments, like a 35kV system, even without external rods, they provide adequate and necessary protection against lightning and transients.

Specifications and maintenance of 35kv light arresters

Knowing the important specifications of the lighting arresters will ensure that they are installed properly and serve their purpose well. On the flip side, proper maintenance will keep the arresters functional and prolong their service life.

Key Features of 35kV Lightning Arresters

• Operating Voltage: 35kV light arresters are designed to operate at 35kV RMS line voltage. This is a high voltage and as such, these arresters are meant for high-voltage substations, power lines, and industrial electrical systems.
• Varistor Rating: The varistor is the heart of a lightning arrester, and it plays a key role in clamping surge voltages. The varistor has to be rated for at least 35kV. Ideally, it should be higher to ensure that the arrester can withstand prolonged voltage stresses.
• Discharge Energy: This indicates the amount of energy from a lightning strike or surge that a single hit can safely absorb. Common values for this specification include joules per disc or joules per varistor.
• Insulation Class: 35kV arresters fall under the C-I insulation class of electrical devices.
• Temperature Range: Often, arresters come with polymer housings and discs that may soften at very high temperatures or lose insulating properties in low temperatures. This is why manufacturers often specify the operating temperature range. Ensure that the materials of the arrester are rated for the ambient temperature range of the installation environment. This is especially important for a 35kV polymer lightning arrester that may be installed in extreme weather conditions.
• Impulse Withstanding: This refers to the ability of an arrester to withstand voltage impulses, such as lightning strikes. Tests are usually done under standardized conditions to measure this.
• Leakage Resistance: After the varistor has been charged by a surge, it is expected to quickly dissipate the energy as heat. Until the varistor is fully discharged, it will continue to present a low resistance path to the electrical current. This is called the varistor's leakage resistance. During this time, the varistor poses a threat to anyone who comes into contact with the arrester. Therefore, good varistors have low leakage resistance.

Maintenance Tips for 35kV Lightning Arresters

• Regular Visual Inspections: For external polymer arresters, a regular visual inspection should be done on it. Look for signs of damage, such as cracks, erosion, or discoloration of the housing. Discoloration is especially a tell-tale sign of damage or degradation due to UV exposure or chemical attack.
• Check the Grounding System: Ensure that the arrester is properly grounded because inadequate grounding will not let the arrester perform its function well. In fact, it may pose a danger in the electrical system.
• Thermal Imaging: Surge arresters that are functioning properly produce almost no heat. If an installed surge arrester is hot during a thermal imaging inspection, it means it is either overwhelmed by frequent surges or it is experiencing heavy electrical current due to surge or lighting. No matter the cause, a hot lightning arrester requires further investigation.
• Regular Interval Testing: There are two key tests done on lightning arresters at regular intervals: insulation resistance testing and power-frequency withstand voltage testing. During insulation resistance testing, a megohmmeter is used to apply a DC voltage to measure the insulation's resistance. For the power-frequency withstand testing, the arrester is subjected to power frequency voltage for an extended period to ensure that it can withstand system voltage. These two tests help to evaluate the condition of the lightning arrester and whether it can still function properly or not.

Commercial uses of 35kv light arresters

35kV light arresters are used for a variety of industrial applications, especially where protection from lightning surges is critical.

• Substation Protection

  Electricity generation substations are responsible for stepping down the high voltages from power plants for distribution. This means that they deal with a lot of transient voltages. Installing 35kV lightning arresters in substations helps protect the substation components, such as transformers, circuit breakers, and switchgear, from damage by lightning and switching surges.

• Power Plant Protection

  In addition to power generation, 35kV lightning arresters are commonly found in hydroelectric, thermal, and nuclear power plants due to their protection from surges. In fact, they are critical for protecting generators, control systems, and other sensitive electronic equipment from transient voltages.

• Industrial Facility Protection

  Manufacturing plants, refineries, and facilities with large industrial machinery and control systems all have high-voltage electrical systems. A 35kV lightning arrester ensures the protection of sensitive equipment from damage by transients to minimize downtime and repair costs.

• Transmission Line Protection

  High-voltage transmission lines are vulnerable to lightning strikes, as they run long distances and are exposed to the elements. Lightning arresters on transmission lines divert the lightning strike's energy safely into the ground to prevent the lines and any connected equipment from damage.

• Renewable Energy Systems

  Coastal wind farms, in particular, are highly exposed to lightning due to their tall structure and exposed location. Other high-voltage components, like transformers and inverters, also require protection. That is why 35kV lightning arresters are used to protect the wind turbines and the electrical system in solar farms, as well, from lightning strikes and other surges.

• Commercial Building Protection

  Large commercial buildings, such as data centers, hospitals, and office buildings, all have high-voltage electrical systems and/or sensitive electronic equipment. There are lightning arresters installed to protect both the building's electrical system and the internal equipment (servers, medical equipment, etc.) from surges. Depending on local regulations and the risk of lightning, arresters may be installed on the building's electrical service entrance or integrated with other surge protection devices.

How to choose a 35kv lightning arrester

A 35kV lightning arrester has to be carefully selected so that it meets the electrical system's specific requirements and provides adequate protection.

• Type

  There are a few types of lightning arresters, and each has its advantage in functionality. Metal oxide arresters, for example, are durable, require little to zero maintenance, and have great voltage-clamping capability. Which makes it preferable in most applications. Ceramic and polymer lightning arresters have external grounding rods to better protect structures like wind turbines and transmission lines themselves. They also make great choices, especially in areas where lightning activity is quite frequent.

• Varistor Rating

  This is probably the most important consideration when choosing the right lightning arrester because the varistor has to be rated for the voltage level of the electrical system, in this case, 35kV. If the varistor is rated lower than the system voltage, it will fail during a heavy surge. On the other hand, an over-rated varistor will lead to poor energy redistribution. Either way, proper varistor rating is crucial for effective protection.

• Environmental Factors

  Weather, location, and application are all important environmental factors that need to be considered. For example, arresters with polymer housings are better suited for coastal or industrial environments with high levels of UV exposure, salt, or chemical because they resist better than ceramic. On the other hand, a ceramic variety would work great in a harsh environment where physical damage is more of a concern.

• Installation and Maintenance

  Ease of maintenance is also something to consider. Polymer arresters are more convenient to install, especially in hard-to-reach areas. Plus, they are lighter. This basically makes them easier to install. Also, the type of housing will impact long-term maintenance. Maintenance-free arresters, for instance, are a more reliable option for installations in remote areas.

• Industry Standards

  Make sure that the selected arrester complies with relevant international and local standards. Some of these industry standards for lightning arresters include ANSI/IEEE, IEC, and other national electric code standards.

Q and A

Q1. What role does a discharge rod play?

A1: Discharge rods basically provide a preferential path for lightning to follow by ionizing the air around it. This is particularly important because it allows the lightning to make contact with the rod instead of other structures nearby, like electrical lines or buildings.

Q2. How does an internal lightning arrester work without a discharge rod?

A2: Internal lightning arresters have a varistor (voltage-dependent resistor) that absorbs and dissipates the surge energy. Even without external discharge rods, these arresters are designed to clamp excess voltage and redirect it through the varistor back to the ground, which is the installation's grounding system. Though the protection offered by internal and external lightning arresters is the same, external discharge rods have the additional benefit of protecting nearby structures like wind turbines and antennas.

Q3. Can a 35kV lightning arrester be used in a non-coastal environment?

A3: Yes, 35kV lightning arresters can be used in non-coastal environments, too. They are designed to protect electrical systems from lightning strikes and transients in any high-voltage environment, regardless of proximity to the coast. Although, the coastal environment does have added protection against lightning with high-stress discharge arresters like this one due to a combination of both external and internal discharge rods. Still, there are plenty of effective 35kV arresters for inland and industrial environments.

Q4. What materials are commonly used for 35kV lightning arresters?

A4: The lightening arresters are usually made of metal, polymer, or ceramic materials. Polymer arresters have a silicone or rubber housing that makes them lighter, more resistant to environmental factors, and maintenance-free. Metal arresters have a metal housing, usually made of aluminum, which makes it a good conductor. Finally, there are ceramic arresters that combine the durability of metal with the insulation properties of the varistor.