Created by: Glen Zhu | Updated Date: January 3rd, 2024
Golf courses, featuring a pleasing environment and comfortable facilities, have become popular resorts for people’s leisure and entertainment. They typically consist of club houses, trolley sheds, shelters, and service stations. Irrigation and sprinklers systems are designed to preserve natural landscape of the greens.
Across the vast expanse of a golf course, where safety is paramount and individual systems operate independently, comprehensive lightning and surge protection measures are crucial to shield against the destructive force of lightning strikes.
The sprawling greens, scattered structures, and exposed equipment are particularly vulnerable to lightning strikes and the resulting power surges, protection designs are vary depending on the specific situations of the system.
Shelters on a golf course offer crucial refuge during sudden downpours, thunderstorms, or scorching heat. How can we protect ourselves from lightning while in the shelters?
The key point is to prevent shelters from lightning interference. Making shelters light-proof, there are few solutions to be considered.
Figure 1 – Risk due to touch and step voltage
Shelters are isolated structures in an open area, which may attract lightning more than those in a cluster of taller objects. Their elevated roof and conductive materials also increase the likelihood of being struck.
A rooftop lightning rod, wall-mounted down conductor and an earth rod comprise to a complete lightning protection system which work together to intercept and safely conduct lightning to the ground, preventing dangerous sparking.
For wood shelters, it is recommended to use a conventional lightning protection system, and consideration must be given to step and touch voltages.
While metal shelters can protect golfers from lightning strikes if properly grounded, with both a metal floor/grid and an earth-termination system. The roof of the shelter must be thick enough to prevent melting during a strike.
If the roof is not thick enough, air-termination rods must be installed and connected to the metal roof to safely conduct lightning currents.
Additionally, isolated air-termination mast could be installed on shelters where the separation distance from the rooftop air-termination system and the down conductor cannot be maintained.
Touch and step voltage is generated when the current flows through the ground, typically in fault conditions such as lightning strikes and faults in electrical systems. Touch and step potential arise from the flow of electricity through the ground, which can create a voltage difference between different points. This voltage difference can pose a shock hazard to anyone who comes into contact with it.
The electric current flowing through the grounded object can create a voltage difference between the object and the ground at the point of contact, leading to touch voltage.
The flow of current in the ground creates a voltage gradient or potential difference in the soil. Step potential occurs when person takes two steps within an area with an uneven voltage gradient.
Figure 2 – Touch and step potential
The severity of touch and step potential is affected by a number of factors, including:
The voltage of the electrical source: The higher the voltage of the electrical source, the greater the touch and step potential.
The impedance of the ground: The impedance of the ground is a measure of its resistance to the flow of electricity. Dry ground has a high impedance, while wet ground has a low impedance. Low-impedance ground will allow more current to flow, which can increase the severity of touch and step potential.
The distance from the source of the leak: The farther away you are from the source of the leak, the lower the touch and step potential.
Touch voltage refers to a person touches a grounded objects while standing on the ground. To prevent touch and step voltage, an adequate safety distance must be required between the lightning rod and the persons in the shelter.
Figure 3 – Installation of a CUI Conductor in case of a small shelter with two air-termination rod and insufficient wall thickness
For a 3m x 3m shelter with a 3m eaves height and a rooftop lightning rod, 10 cm wooden beams are needed. If the shelter has a minimum height of 3m, the safety distance from the rooftop lightning rod is maintained.
The difficulty arises in maintaining a sufficient distance from outer walls, requiring adequate wall thickness in the construction. Earth rods, of specified length and suitable material, are commonly used to connect the lightning rod to the ground. Earth rods are vertically buried in the ground, typically 6m to 9m deep, depending on the ground type.
Log-structured shelters usually have the demanded wall thickness. Shelters with thin wood walls may require down conductors installed near outer edges for maximum thickness or use an isolated lightning protection system.
Highly insulating lightning rods, such as CUI Conductors, can be used to maintain the required safety distance. The use of an isolated lightning protection system is suggested as an alternative. Highly insulating lightning rods, like CUI Conductors, are proposed as a solution for maintaining safety distances.
The insulated down conductor has to be installed vertically up to a height of 3 meters above ground level. The upper end of the conductor has to be connected with the air-termination conductor, the lower end with the earth-termination system by means of a clamp.
When high lightning voltage flows into the ground, if a person with a significant ground potential difference stands with their feet at different points on the ground, they may experience a voltage difference between their feet. It is referred to as step voltage.
Figure 4 – Insulation of the floor by means of asphalt and a wood floor
The prevention of dangerous step voltage is to insulate the floor. This can be achieved with a layer of asphalt or a well-ventilated, dry wooden floor. Preventing plant growth through the shelter is also crucial for safety.
Placing a finely meshed metal grid under the standing surface of people provides protection against electrical hazards. This grid, ideally made of stainless steels round conductors, should be installed close to the ground surface and connected efficiently to ensure long-term effectiveness.
Club house is a central facility that serves as a hub for various activities and amenities related to the golfing experience. Surge protection for this multi-functional house is very necessary to keep the whole house safety.
The club house is a complex of various systems and equipment, the best approach is to apply cascaded surge protection to protect specific equipment or systems. And each system could be individually protected while integrated into the whole power supply system.
Figure 5 – Surge protection for the club house
The power supply feeder cable to the main low-voltage distribution board in the clubhouse, along with sub-distribution boards serving various areas, is often located in the basement.
For surge protection for the incoming power line, a type 1 surge protector is recommended for the main distribution board to prevent lightning currents, regardless of external lightning protection. The configuration depends on working systems.
Sub-distribution boards are equipped with type 2 surge protectors to protect power supply for other electrical equipment in the house.
Telephone/data lines typically terminate in a dedicated service room, with a type 1 surge protector for IT equipment installed at the entrance point. To further protect the telephone lines, FRD2-110 or FRD4-110 could be installed on incoming phone lines before they enter the building.
RF Coaxial Surge Protector DS-UHF F/M
Office communication and RFID systems are crucial, they play an important function for ball machines, access control and renting of golf carts. RFID systems also can be used for real-time location tracking and emergency warning, therefore it is required PoE surge protection for LAN connections and a type 3 SPD for power supply.
Additionally, protective circuits for antennas (RFID, TV, radio) near the entrance point should be safeguarded. A free-standing air termination is mounted next to the Satellite antenna to prevent the side flashover. Proper separation distance should be maintained as well.
The implementation of measures to prevent excessively high step and touch voltages during lightning interference is crucial. Protective measures, especially in frequently used entrance and shelter areas, are essential. Various strategies can be employed, such as maintaining a surface resistance of ≥ 100 kΩ within a limited protective area of 3 m around the down conductor, for instance, using 5 cm asphalt.
Lightning equipotential bonding must be applied to different systems directly at the building’s entrance point. Additionally, depending on the results of the risk analysis, surge protection measures upstream of terminal devices may be necessary.
Similar protection measures employed for the clubhouse or trolley shed with a driving range should also be implemented for the golf cart parking garage and cart shed.
The well-maintained golf course greens benefit from the mature irrigation system. However, in the summer months, extended power surges resulting from tropical storms or hurricanes could pose a threat to the integrity of our irrigation system.
The results in a surge of alternating low and high pressure can cause cracked pipes, damaged pump casings, valve damage and leak. So how to protect irrigation system from power surges?
The irrigation system starts with a water source, water is primarily pumped from reservoirs, with the necessary pumps situated in underground ducts and centrally controlled and monitored from a service station.
The pressurized water pipe spans the entire golf course, supplying sprinkler systems that, in turn, water the individual greens and tees through branch pipes. Magnetic valves, either directly installed at the sprinkler or in ground-level boxes, control the water flow.
These valves, activated by decoders, are powered and receive data transmission through a two-wire ring conductor, which can extend beyond 10 km in some cases. To limit excessive voltage drop, connecting cables to the magnetic valves do not exceed 150 m.
Figure 6 – Overview of the irrigation system
Due to the length of the two-wire ring conductor and the extended conductors to the magnetic valves, the highest risk of surges will occur.
Therefore, surge protective devices are strategically installed on the two-wire ring conductor at intervals not exceeding 150 m. Type 1 surge protector is integrated into the wring system of golf course and channel the surges away from the conductors (Figure 5).
Besides, proper grounding must be implemented to work with surge protectors to direct the power to the path of the least resistance. Corrosion protection for earthing system is required to made. These should be implemented simultaneously with the installation of the pressurised water reticulation pipe and the two-wire ring conductor.
A simple isolation could also help prevent damage, just unplug the system when unnecessary. If possible, manually disconnect the irrigation system from the power source during thunderstorms and avoid peak lightning season. This offers the best protection against direct strikes.
Service station plays a crucial role as it is equipped with power distribution, control cabinet of the irrigation system, PC, interface and data management system. There is no doubt that lightning and surge protection is the top priority owing to safety concerns.
Lightning equipotential bonding must be established at the entry point into the service station, encompassing the pressurized water pipe, the two-wire ring conductor, the IT system, and the power supply feeder cable, as well as the pump line.
The need for additional surge protection measures for internal conductors preceding the respective control systems depends on the size of the building.
LSP’s reliable surge protection devices (SPDs) are designed to meet the protection needs of installations against lightning and surges. Contact our Experts!
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