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  Total Solution for Solar Power Plant  


Solar energy, one of the mainstream energy resources, is becoming more crucial, especially in electricity generation, due to its cleanness and infinity recyclable. Thus, solar energy is an excellent choice to alleviate energy shortages and environmental problems other than fossil fuels.In Thailand, near the equator, there is a high solar energy intensity; therefore, electricity generation from solar energy is advisable. Moreover, since the government subsidizes the alternatives of electricity-generating energy for national electricity stability, there have been various solar powerplant constructions in recent years.

Kumwell creates a solution, “Grounding and lightning protection for solar power plant,” to create a solar system’s safety and durability. The solution can protect damage from direct lightning strikes and impulse electromagnetic to solar panels or electronic devices.

 
PV Module direct lightning protection by Self-Standing Lighting Pole
 
  • Solar power plants usually use PV module panels (Photovoltaic Module) to convert from solar to electricity. Nonetheless, most PV module panels are exposed to direct lightning because the solar power plants' PV module panels are often built in the massive open area.
 
  • To conserve the PV panels, installing individual lightning protection systems (lightning poles) is advised to cover direct lightning strike damages. The lightning pole installation needs to distance away from the PV panels at least equal to the calculated separation distance "s", according to IEC 62305-3 standard, to prevent flash damages from air termination.
 
  • The Self-Standing Lightning Pole has a smaller design than ordinary poles, preventing overshadowing PV modules. Also, the pole is light (easy transportation), easy installation, and high strength (Wind load tested up to 150 km/hr.).
PV-Module defending against flashover by KHV cable
 
  • Flashover between air termination system and PV-Module prevention can be implemented by distancing both devices at least equal to the separation distance “S”.
 
  • In insufficient distancing, down conductors are needed, averting induction or side effect to devices. The averting can be done by implementing Isolated Air-Terminal, using KHV-coated down conductor cables. The KHV cable can resist lightning impulse voltage and compensate for the separation distance “S” in 0.5 m.
 
  • KHV cable passes lightning impulse resistance according to IEC 62561-8 Standard (Requirements for Components for Isolated LPS)
Thievish risk reduction by Anneal Copper Clad Steel Wire grounding

  • Since most solar powerplant located in massive open areas, it is hard for regular inspection. Therefore, there are many bare-copper thievery cases, resulting in invaluable powerplant operating disruption.
 
  • The IEC 62305-3 complied grounding conductors can be substituted with annealed copper-clad steel wires, reducing bare copper thefts.
 
  • The annealed copper-clad steel wire has high corrosion resistance in the neutral ground and passes IEC 62561-2 standard.
Device surge protection by SPD (Surge Protection Device)

  • Direct lightning strikes or nearby lightning strikes can create surges, inducting electromagnetic. The surges pass through signal cables, such as grounding electrodes, electric wires, AC/DC, telephone lines, Lan cables. Therefore, Powering on and off some electric equipment can cause equipment harm from the surge.
 
  • Kumwell SPD covers all AC power supply, DC power supply, transmitter unit, data/signal line.
 
  • Kumwell SPD passes IEC 61643 standard (Low-Voltage Surge Protective Device).


  Total Solution for Substation  


Substations, an essential part of electrical distribution-receiver systems, are responsible mainly for voltage converting and electrical distribution stability. Low resistance grounding systems are required to minimize substations’ error, transferring excessive electric current to the ground as fast as possible. If there is a fault in the grounding system, the surplus electric current will flow to the system, risking users’ lives and devices. Therefore, Kumwell presents a solution, “substation grounding system design,” facilitating in creating low resistance grounding system to achieve substation safety, reliability, and effectiveness.
 
Lowering substation grounding system resistance by MEG
 
  • IEEE Std 80-2013: IEEE Guide for Safety in AC Substation Grounding is a substation grounding standard, creating safety for equipment and users. In the design, conductors need to be planted as a ground grid formation surrounding the area, with ground rods as an enhancement.
 
  • Most grounding design’s goal is to have a low resistance system. Nonetheless, area inadequacy and high resistance areas (seashores, hills) construction are common design issues—consequently, increasing conductors and ground rods or increasing ground rods length may be insufficient in grounding resistance reduction.
 
  • IEEE Std 80 recommends reducing ground resistance by using low-specific resistance ground enhancement materials, placing around conductors, or ground rods. This procedure adds more touchpoints to the surfaces reducing ground resistance, similar to ground rods or conductors’ size increasing.
 
  • Kumwell MEG (More Effective Grounding) is a ground enhancement material. It does not corrode ground conductors or ground rods. It is also forever lasting, environmentally friendly, and has significantly low specific resistance at 0.03-ohm meter. Moreover, Kumwell MEG passes IEC 62561-7 standard test (Requirements for earthing enhancing compounds).


  Total Solution for Transmission Line Tower  

 
Transmission line towers are the major part of electrical system, distributing energy via country-wide electrical network from productions to end users. Therefore, transmission line towers are an aorta of the energy ecosystem. Nonetheless, the tower can often be the cause of the broad backout because most of the transmission line towers are built in high impedance area (stone areas or mountain), having high chance of black flash over when the lightning strikes. The blackout crucially damages macro economy and lower foreign investor’s trust. Hence, to improve electrical distribution system reliability, Kumwell presents a solution, “Transmission line tower grounding systems preventing back flash over”, to create safety and be a transmission line tower grounding design model.

Back flashover prevention by high voltage electrical pole grounding design
 
  • When a stroke contacts a tower, a portion of the stroke current travels down the tower. The remainder passes out along the OHGWs. The initial fractions along these two paths are determined by their relative surge impedances. The tower current flows to earth at the base of the tower through the tower footing impedance. The resultant voltage drop, are the magnitude of the voltage wave reflected back up the tower, depend directly on the value of the footing impedance encountered by the current.
 
  • Reducing grounding’s impulse impedance can lower impulse voltage across the insulators. The reduction can be implemented by groundings design considering effective length as a priority.
 
  • The ground electrode designs, reducing impulse impedance, can be executed by applying counterpoise formation, which is planting effective length conductors extended from each of the transmission towers in the area. The conductors need to be paralleled with the transmission line, in which planting more ground rods are allowed.
 
  • In the high soil resistivity areas, such as seashores or hills, ground resistance can be reduced by using MEG (More Effective Grounding) placing around the conductors under the effective length condition. Consequently, ground potential is raised and back flash over is prevented.
 
  • Kumwell MEG is a ground enhancement material. It is non-corrosive to conductors, long-lasting, and environmentally friendly. Also, the MEG has a significantly low resistivity as 0.03 ohm-meter, and passes IEC 62561-7 standard test (Requirements for earthing enhancing compounds).
 

 Total Solution for Solar Rooftop 
 
Nowadays, the trend of installing solar rooftop systems for electricity generation from solar energy is increasing in popularity in buildings such as offices, homes, and restaurants, as well as buildings that consume electricity during the daytime. Because cost-effective, reduces expenses and reduces environmental impact. However, there is a high risk of damage from direct or indirect lightning strikes due to the installation of solar panels in open spaces. Therefore, to ensure that the solar power generation system works continuously and efficiently, Kumwell provides a solution for "Lightning and Surge Protection for Solar Rooftop System for Electricity Generation from Solar Energy Installed on the Roof."
Designing Lightning Protection System for a Building with Solar PV Panels installed on the roof

  • Air-termination system
  1. Design according to TISI (Thai Industrial Standards Institute) or IEC (International Electrotechnical Commission) lightning protection standards, ensuring that all PV modules are located under the protected area of the air-termination system.
  2. If separation distance (S) between air-termination system and PV modules can be reduced, bond the metal parts of the modules with the air-termination system.
  3. For existing buildings that need solar PV panels on the roof, to protect PV modules from lightning strikes, it is recommended to use stainless steel round conductors with a diameter not less than 10 mm. The conductors should be bent into a lightning receptor shape to avoid corrosion with the original air-termination system (stainless steel conductors can be connected to copper and aluminum conductors).
  • Down-conductor system
  1. The arrangement of the system, distance between down conductors, material and minimum size of the conductors are designed according to lightning protection standards such as TIS or IEC, like the design of general buildings.
  • Grounding system
  1. The grounding system for lightning protection should be arranged in a ring loop around the building to ensure electrical equipotentiality between all down-conductors at ground level, and in cases where other systems, such as electrical power, are grounding and bonding should be carried out to connect those systems to the grounding system for lightning protection, to limit the potential difference between different grounding systems.
  2. The conductor in the grounding system can be made of annealed copper clad steel wire to reduce the risk of theft. This type of wire is also resistant to corrosion in normal environmental conditions (copper) and can be used as a conductor according to lightning protection standards such as TIS and IEC.

Lightning protection for buildings equipped with solar power systems installed on the roof

  • The selection of Surge Protective Devices (SPDs) to protect against overvoltage caused by lightning strikes and electrical switching to prevent damage to equipment in solar power systems installed on the roof depends on the installation method of the PV module.
  • Installation of PV Modules without external lightning protection system
    • Install SPD Class II tested by IEC 61643-31 at positions 1 and 4 on the DC side of the inverter.
    • Install SPD Class II tested by IEC 61643-11 at positions 2 on the AC side of the inverter.
    • Install SPD Class I or Class II tested by IEC 61643-11 at position 3 on the AC side of the inverter.
  • For PV module systems with external lightning protection and can maintain a separation distance (S) between the air-terminal and the PV modules
    • Install SPD Class II tested by IEC 61643-31 at positions 1 and 4 on the DC side of the inverter.
    • Install SPD Class II tested by IEC 61643-11 at position 2 on the AC side of the inverter.
    • Install SPD Class I or Class II tested by IEC 61643-11 at position 3 on the AC side of the inverter.
 
  • For PV module systems with external lightning protection but cannot achieve separation distance (S) between air-terminal and PV module
    • Install SPD Class I tested by IEC 61643-31 standard at positions 1 and 4 on the DC side of the inverter.
    • Install SPD Class I tested by IEC 61643-11 standard at positions 2 and 3 on the AC side of the inverter.
Contact Center
Tel : 02-954-3455
E-Mail : info@kumwell.com
Kumwell Corporation Public Company Limited
358 Liang Mueang Nonthaburi Road, Bangkrasor,
Muang, Nonthaburi, Thailand 11000