WO2005083863A1

WO2005083863A1 - Lightning arrester with accelerated ionization of air

Info

Publication number: WO2005083863A1
Application number: PCT/PL2004/000103
Authority: WO
Inventors: Eugeniusz Smycz
Original assignee: Eugeniusz Smycz
Priority date: 2004-02-26
Filing date: 2004-12-08
Publication date: 2005-09-09
Also published as: CN100474724C; CN1890851A; RU2336617C2; RU2006133827A; PL365619A1; EP1745534A1; PL204398B1

Abstract

A lightning arrester with accelerated ionization of air around its spike consisting of main ionization electrode, connected in series, through high voltage coil and magneto, with earthing electrode, characterized in that the high-voltage coil (4) is located in metallic reinforcing electrode (3) with its plugged upper face connected to the spike (2) of the main ionization electrode (1), whereas the space between reinforcing electrode (3) and high-voltage coil (4) is filled with solid-state dielectric (9). The reinforcing electrode (3) is made of metal, preferably of steel sheet or in form of metal plated coating.

Description

Lightning arrester with accelerated ionization of air

The object of this invention is the lightning arrester with accelerated ionization of air, to protect building structures against atmospheric discharges. In certain atmospheric conditions clouds, laden with negative electric charge directed towards earth may gather. In case such charge is too large, and the intensity of electric field exceeds a certain threshold, a complete electric discharge, or flashover takes place. Original flashover causes ionization of air atoms along a path of 10 - 20 meters, with subsequent ones ionizing further atoms and causing avalanche ionization and, upon reaching earth, a sudden discharge and a flow of positive charges, collected in the ground, take place towards the negatively charged cloud. Lightning arresters of various designs are applied to direct electric discharge and to control the flow of charge from cloud towards the ground. Commonly known Franklin's lightning arrester of the simplest design constitutes a metal rod connected to earth and pointed at one end. The rod spike, located in strong electric field, causes ionization of air in its surrounding space. Its principle of operation consists in creating of two channels that conduct generated ions - negative one, from cloud to the ground, and the positive one, with some delay, from lightning-arrester spike towards the cloud, whereas the higher they meet the higher the lightning-arrester efficacy. Also, it was found that the lightning-arrester efficacy is the higher the quicker the ionization taking place around its spike to provide an inception for generating a second channel that conducts towards the cloud, whereas various known methods exist to raise this effectiveness. One of these methods consists in air ionization by means of an radioactive source in order to generate free electric charges around lightning-arrester spike. A drawback of this solution is that, at the moment of lightening strike, the radioactive element becomes torn apart, thus causing radioactive contamination of the atmosphere. The other known method to accelerate air ionization consists in air ionization with earth- connected piezoelectric element, with which the lighting rod and additional electric wire are equipped. The principle of operation of this lightning arrester consists in converting of wind- strength-caused mechanical movements of the lighting rod into high-voltage pulses ionizing air under the effect of lighting-rod pressure onto piezoelectric element. However, this lightning arrester functions only with wind being present. Also known is the method of accelerated air ionization by means of electric pulses around lightning-arrester spike, which is isolated from earth by a capacitor and electronic system. In this method the lightning-arrester spike is charged electrically during the storm, and the collected charge is stored in capacitor of electrical system and then converted to high-voltage pulse which raises the electric potential of the spike, thus accelerating air ionization around it and, at the moment of lightning stroke, an electric discharge takes place between capacitor electrodes. This type of lightning arrester has this drawback that capacitor electrodes are not connected with the metal element and therefore, in case of damage to electronic system, this lightning arrester becomes completely ineffective. Also known is the method of accelerated air ionization around the spike of main lightning-arrester electrode by means of additional two electrodes located below the spike where electrodes and the spike are connected with earth through electronic system containing collecting electrodes. These electrodes collect electric charges converted by electronic system to high voltage supplied to side electrodes, causing air ionization near the spike of main electrode. In this method the air ionization takes place through side electrodes below the main electrode thus limiting the effectiveness of this lightning arrester. The accelerated air ionization, with simultaneous protection of main electrode spike against damage, was achieved also by applying lightning arrester according to Polish patent application P-332387 consisting of main ionizing electrode provided with discharge electrode, connected in series with earth through coil and magneto and of at least one collecting electrode connected directly with earth. In this lightning arrester the collecting electrode is located opposite and near the discharge electrode, whereas the magneto consists of the spike and a flat electrode located opposite it. In this solution, the electric field from charged cloud, or from atmospheric discharge descending towards earth, concentrates on lightning-arrester spike, which fulfils the role of electric-field collecting electrode, and then the electric potential is transferred on the spike of magneto, thus initiating ionization between it and flat electrode, which in turn causes a raising of potential on the spike of the main ionization electrode and initiates air ionization around the spike. It was found that the efficacy of lightning-arrester functioning depended significantly on the level of ionization current, i.e. the flowing electric charge having its beginning at the spike of its main electrode, as the generated ions are the source of avalanche reaction accompanying the electric breakdown of air. The objective of this invention is to develop a simple and reliable lightning-arrester design enabling accelerated ionization of air around its spike as well as a simultaneous significant rise in the effectiveness of its functioning. The essence of the design solution of the lightning arrester of this invention is that its high- voltage coil is located in metallic reinforcing electrode with its top face plugged and connected in series with the spike of main ionization electrode, whereas the space between this coil and the reinforcing electrode is filled with solid-state dielectric, preferably polyurethane resin. The diameter of the reinforcing electrode equals 1.3 to 5.0 diameters of the high-voltage coil. The reinforcing electrode is preferably made of metal, especially steel sheet. It is also preferable that the reinforcing electrode is made in metal coated form. It is also preferred that the reinforcing electrode has a diameter within 20 mm and 100 mm, most preferably 50 mm, its length is within 50 mm and 1000 mm, preferably 350 mm, and its thickness is within 0.2 mm and 50 mm, preferably 2 mm. The unfolding bottom-up ionized air path weakens its strength, thus creating potential for easier breakdown between the front of descending lightning stroke/atmospheric discharge. In turn, the high pressure fulfils a barrier function for sudden current surge, causing lightning stroke discharge from external electrode to the earthing electrode, thus omitting the center of the lightning arrester and, in consequence, the coil with magneto are protected against damage. The object of the invention will be described closer in its embodiments shown in the drawing where Fig. 1 is a schematic diagram of lightning arrester with accelerated ionization of air and fig. 2 is a schematic diagram of modified embodiment of this lightning arrester. The lightning arrester with accelerated ionization of air, shown in fig. 1, consists of main ionization electrode I provided with spike 2, connected in series through reinforcing electrode 3, with high-voltage coil 4 and the spike of magneto 5 located opposite its flat electrode 6 connected with earthing electrode 8 through external electrode 7, whereas the top member of external electrode 7 is located opposite main ionization electrode 1 and the space between the main ionization electrode , external electrode 7, earthing electrode 8, and inside the reinforcing electrode 3, is filled with solid-state dielectric 9, preferably polyurethane resin. The earthing electrode 8 is constituted by a thin metal coating plated by spraying on plastic pipe 10, plugged from the side of main ionization electrode i, with bottom plug ϋ, and its outlet situated above magneto 5. The reinforcing electrode 3, lOOmm-long and 50mm in diameter, has 0.2mm -thick metal coating, plated by spraying on plastic pipe J_0, whereas the reinforcing electrodes with lengths of 50 mm and 500 mm and diameters of 20 mm and 100 mm were applied in other embodiments of the invention. In the second embodiment of the invention, shown in fig. 2, the lightning arrester consists of air-ionizing spike 2 that is connected in series, through tubular reinforcing electrode 3, with high- voltage coil 4 and the spike of magneto 5, located opposite its flat electrode 6 connected 110 with earthing electrode 8, whereas the flat electrode 6 is located near the outlet of the tubular reinforcing electrode 3. In this case, the reinforcing electrode 3 is made of metal pipe of the thickness 2 mm, the length 350 mm and diameter 75 mm, plugged at one end, whereas the reinforcing electrodes with thickness 1.0 mm, length 100 mm and diameter 25 mm or with thickness 5 mm, length 500 mm and diameter 75 mm or with thickness 50 mm, length 1000

115 mm and diameter 100 mm were applied in other embodiments of the invention. Application of reinforcing electrode 3 enables collecting a larger electric charge induced by electric field of the atmospheric discharge and creating a scattered capacitance system between this electrode and the high-voltage coil providing electric current, i.e. ionization current, to a ion generating system.

120 By trials-and-tests method the optimum dimensions of reinforcing electrode 3 were determined along with the finding that enlarging the electrode diameter causes a rise in electric charge collected while a raising of distance between high-voltage coil 4 and reinforcing electrode 3 decreases the capacitance whereas enlarging of the diameter of this coil worsens its efficiency.

125 Therefore, the optimum conditions are created when the diameter of the reinforcing electrode 3 equals 1.3 to 5.0 diameters of high- voltage coil 4. At coil diameter 30 mm the optimum diameter of reinforcing electrode 3 is 50 mm. In turn, if the resistance to wind should be increased, the optimum length of the reinforcing electrode 3 shall be 350 mm. In the lightning-arrester embodiment shown in fig. 1, the existence of direct current flow is

130 not manifested as the potential of high- voltage coil 4 is, all along it, the same as that of the reinforcing electrode 3 and, in case of current flow decay through this coil, a voltage drop takes place all along its length and, a resulting potential difference appears between external coil sections of this coil and the reinforcing electrode 3. Then a discharge of scattered- capacitance capacitors, i.e. supplying of electric energy in the form of additional current in

135 high- voltage coil 4. takes place in form of harmonic high-frequency current transients. Thus ensuing new, high, harmonic high-frequency current transients are the generators of additional overvoltages that augment ionization around the spike 2 of the main ionization electrode L Due to this solution, a several times higher ionization current was obtained and the

140 lightning-arrester effectiveness rose nearly twice as a result. In turn, in the lightning-arrester embodiment shown in fig. 2, the reinforcing electrode 3 is utilized for electric-discharge current transferring towards earthing electrode 8, equivalent to external electrode 7, shown in the embodiment in fig. 1. This requires reinforcing electrode 3 made of thicker metal for this case, compared to electrode in the first embodiment, which may

145 have only a thin metal coating.

Claims

Patent claims

What is claimed is: 1. A lightning arrester with accelerated ionization of air around its spike consisting of main ionization electrode, connected in series, through high voltage coil and magneto, with earthing electrode, characterized in that the high-voltage coil (4) is located in metallic reinforcing electrode (3) with its plugged upper face connected to the spike (2) of the main

5 ionization electrode (1). 2. A lightning arrester according to claim 1, characterized in that the space between the reinforcing electrode (3) and high-voltage coil (4) is filled with solid-state dielectric (9). 3. A lightning arrester according to claim 1 or 2, characterized in that the solid-state dielectric is preferably a polyurethane resin.

10 4. A lightning arrester according to claim 1, characterized in that the diameter of reinforcing electrode (3) equals 1.3 to 5.0 diameters of high-voltage coil (4). 5. A lightning arrester according to claim 1, characterized in that the reinforcing electrode (3) is made of metal, preferably a steel sheet. 6. A lightning arrester according to claim 1, characterized in that the reinforcing electrode 15 (3) is made in form of metal plated coating. 7. A lightning arrester according to claim 1, characterized in that the reinforcing electrode (3) has a diameter within 20 mm and 100 mm, preferably 50 mm. 8. A lightning arrester according to claim 1, characterized in that the reinforcing electrode (3) has a length within 50 mm and 1000 mm, preferably 350 mm. 0 9. A lightning arrester according to claim 1, characterized in that the reinforcing electrode (3) has a thickness within 0.2 mm and 50 mm, preferably 2 mm.