WO2007135474A1

WO2007135474A1 - Electrical equipment that stores energy generated by a lightning bolt

Info

Publication number: WO2007135474A1
Application number: PCT/IB2006/001771
Authority: WO
Inventors: Luis Raul Arnedo Gonzalez
Original assignee: Luis Raul Arnedo Gonzalez
Priority date: 2006-05-23
Filing date: 2006-05-23
Publication date: 2007-11-29

Abstract

The electrical equipment that stores the energy generated by a lightning bolt is constructed by placing, in parallel, a condenser (1) of 30 μF, 500 kVAr, 6640 V, with a resistance (2) having a value less than or equal to 33.67 Ω, and a conductive protective mesh (4) of copper insulated from earth by electrical insulators (6). Said equipment stores pulse currents from 200 000 A and upwards and this energy is stored or dissipated within the equipment within a maximum period of milliseconds, and the maximum voltage value which the equipment resists in microseconds is 200 000 V.

Description

ELECTRICAL EQUIPMENT THAT SAVES THE ENERGY GENERATED BY AN ELECTRIC RAY

TECHNICAL SECTOR

The present invention relates to an Electrical Equipment that allows when an electric shock or lightning strikes or a high voltage short circuit occurs, the energy generated in this equipment is saved.

BACKGROUND OF THE INVENTION,

The main objective of the earth meshes is to guarantee the safety of personnel during electric shocks or electrical failures, the magnitude of the current to be dissipated, the duration of the fault and the resistivity of the land such as size and shape of the mesh.

The history of the IEEE 80 Standard "Guide for safety in AC substation grounding", has been quite difficult to handle because of its large percentage of empiricism presented, for example in 1961 Walter Koch wrote a version of the standard and proposed one of the most confused and discussed, the irregularity factor Ki which tries to consider that the currents Mesh is not distributed proportionally but they have the tendency to present higher current densities in the corners, then the problems of Ks, Km, not only because not enough data are available on the conditions in which Koch had worked but because The application of the formulas frequently leads to physical impossibilities or design contradictions,

Another problem that arises is the value of the current that must dissipate the mesh. The values used by the companies varied more or less arbitrarily between 30% and

100% of the fault current found using conventional short circuit techniques. Because the amount of driver required is proportional to the current, the cost and security varied greatly.

In the 70s, innumerable articles appear in the literature of grounding questioning the gaps, theories and techniques developed in the norm and it became fashionable to show physical inconsistencies in the application of the same. The standard was revised in 1974 but no major modification was made and the 1976 guideline was virtually the same.

In 1978, the IEEE created a working group with the intention of clarifying the mysteries that can be summarized as follows: 1. Confusions about Ki, Ks, Km.

2. Set limits of application to the equations.

3. Establish methodologies for the calculation of the current that must dissipate the mesh. 4. Consider the influence of the rods on the behavior of the mesh.

5. Expand the application to non-uniform floors.

6. Review the influence of the gravel layer on tensions tolerable by man. 7. Examine the possible use of materials other than copper in the mesh. 8. Try to systematize the analysis of earth meshes.

The group tried to repeat Koch's experiments, but due to economic limitations in the early 1980s, it had to actively include the participation of the EPRI who, in the company of the University of Ohio, built scale models for two-layer terrains and proposed a calculation methodology,

Another working group on resistivity measurements using three and four electrode methods. Georgia Tech produced a series of computer programs to determine the division of fault currents, process resistivity measurements and design the mesh. The last revision of the norm in 1986 failed to include much of the results of These studies due to time constraints, however, it is expected that this valuable information is in new editions of the standard.

The work has not been completed and, in particular, research is still being carried out on the effects of currents on the body, the understanding of the different layers of the soil, the development of increasingly precise computer programs with fewer limitations and even on considerations Probability statistics that will undoubtedly impact future editions of the standard.

In July 1999, at the National University in Bogotá, an International Grounding Seminar was held and the following conclusions were reached:

1. The issue of earth meshes is still today one of the most dynamic of engineering.

2. The main problems that remain in the design of the mesh to ground are the characterization of the terrain, the determination of the current that must dissipate the mesh and the calculation of the potential for passage, touch and transfer.

3. The simplified method of the standard produces safe results (although very conservative) when its limitations of applicability are respected. 4. When the ground mesh does not have the characteristics required for the use of the simplified method, or when it is desired to make an optimized design, the use of the two layer model is recommended. 5. Even the two-layer method has important limitations when the terrain cannot be perfectly characterized as two-layer, so that an appropriate engineering criterion must be applied to adjust it. 6. There are still many issues to be resolved in the IEEE 80 standard related to the current carrying capacity of man, the characterization of land with more than two layers, the limitations of the two-layer method, other considerations on the resistivity of the layer of rubble in wet weather, probabilistic considerations on the resistivity, the probability of occurrence of the worst failures and their simultaneity with the presence of personnel in the substation, the inadequate location of the affected person and the timely non-operation of the protections, considerations that should lead to a more optimal design.

From the previous conclusions, we see that the twentieth century had problems to design earth meshes, there are many unresolved problems on the issue of grounding, all the writings agree that a good earth design is very important for the operation of the system and personal protection, in Failure conditions the flow of current to earth produces tensions inside and outside the equipment to be protected, it is known that the potential gradients can be so great that they cause serious danger to people who are walking in the area. "It should be emphasized that a substation with low resistance is not in itself a guarantee of safety, the IR product where 1 is the maximum short-circuit current flowing and R Ia resistance, must be quite low so that there is safety in the area".

In Colombia, in a span of 20 years the major cause of disturbances (58%) in the ISA electrical interconnection network, was caused by atmospheric electrical discharges. The Bogotá Energy Company spent an annual amount of US $ 2,500.00 in replacement of distribution transformers during the period from 1994 to 1996. In another study conducted at another energy company, after examining 205 rural distribution transformers, it was found that Only 8% had a 5 ohm earth resistance. Likewise, the premiums currently paid by the insurance sector for these concepts are very high,

Worldwide of the 55 large fires of 52 oil tanks were caused by electric rays. Another major problem today is the grounding of communications systems.

In Colombia there is the Colombian technical standard for lightning protection NTC 4552 of 1993. It is said that more than 2000 storms are active simultaneously producing approximately 100 electric shocks per second. Electric rays caused 47% in 1996 and the

69% in 1997 of outputs of 230 KV and 500 KV transmission lines, the average number of deaths is 100 people per year.

In the last 20 years, techniques and elements have been developed that improve the behavior of the earthing system such as: shielding, shielding, electrodes for landing and chemical materials for the treatment of the ground that allow reducing the resistivity.

Currently the high-voltage grounding and communications systems are made by placing copper rods or mesh with the objective of reducing the earth resistance to the ideal of zero ohms or using the equipotentiality theory, according to which at the time in the that an electric shock to ground or "lightning" occurs a high-voltage transient effect that, due to the physical design provision, causes all equipment and people to be are in the equipotential zone have the same voltage and are protected in that zone only.

The first technique described has the disadvantage that occurs over tensions that cause damage to the equipment and people who are in the discharge zone.

The second technique (equipotentiality) has the disadvantage that voltage differences can occur in the protected area and therefore cause damage.

ADVANTAGES OF THE INVENTION

The electrical equipment that stores the energy generated by an electric beam, has the following advantages in relation to the state of the art systems such as:

> With the equipment of the invention, a complete protection of the equipment and people that are in the area affected by the electric beam or a short circuit is achieved; since they will not occur over voltage or current in said area, whereby 100% protection is obtained with the electrical equipment of the invention. > In areas where there is a large number of electric drops, a new energy source is obtained.

> The electrical equipment protects up to the IERC 61312 standard, which defines the maximum pulse of the most unfavorable current in 200 KA and which are produced with only 0.1% possibilities.

RELATIONSHIP OF ANNEXED FIGURES.

Figure 1. Perspective of the Electrical Equipment of the Invention.

DESCRIPTION OF THE INVENTION

The present patent application relates to an electrical equipment that saves the energy generated by an electric beam; said invention is based on seeing the earth as a differential equation and not as a simple resistance. This change of paradigm allows to enter into mathematical concepts of design of the control theory that says that it is possible to change the transients and the forced responses of the differential equation to values that are needed. The earth has resonance at frequencies between Hz and 4 Hz, which indicates that a second order differential equation is minimal. The above allows to identify the land between damping factors of 0.1 to 0.7; This with an experienced team was able to find the differential equation with which the Electrical Equipment of the present invention was designed, as follows:

S + a = 0

Where a is the root of the first order differential equation that is comprised in the ranges of the transform of

Place between - ⁰⁰ and zero.

The Electrical Equipment of the present invention in said range saves the energy generated by the electric beam or by the short circuit, as seen in Figure 1, is constructed by placing the capacitor 1 in parallel with the resistor 2, in this way the equipment acts as a new electrical earth, whereby all downspouts 3 of the equipment or structure to be protected must be carried to this equipment, which comes from a lightning rod 5.

The resistance used has a value less than or equal to 33.67 Ω, for a capacitor of 30 μF. At a lower electrical resistance in Ω that is placed in the 30 uF capacitor, the designed equipment will store greater impulse current.

In areas that require greater protection, a conductive protective mesh 4 of ground insulated copper with electrical insulators 6 is placed, which will allow the electrical rays or the short circuits that fall to it to be absorbed by the electrical equipment of the invention, due to to which the mesh 4 is connected to the equipment by the copper conductor 7.

The Electrical Equipment is designed to store impulse currents up to 200,000 A, this energy is not grounded but is stored or dissipated in the equipment of the invention, in a maximum time of milliseconds, with this we achieve the purpose of protecting people and equipment that are on the ground, therefore it can be used as a new source of energy.

All the previous design is based on the Control Theory that has been deduced from the experimentation carried out with the differential equation that saves energy, by which all electrical equipment

that is in the range of - °° and zero, roots of the Laplace transform is part of the present invention. EXAMPLE 1 OF APPLICATION.

According to the previous thing, applying the first order differential equation, when a single phase capacitor of 30 μF is placed, the electrical resistance is 33.67 Ω, it has:

S + 990 = 0

The electric capacitor has the following specifications: 500 KVAR (reactive kilovoltages), 6640 V.

Maximum value of voltage that the equipment holds in microseconds = 200,000 V.

Dimensions:

Length: 45 cm Width: 14 cm

High: 1 m

Weight = 43.1 kg

The electrical resistance must be constructed with a tube in alumina ceramic, with a diameter of 8.89 cm and a length of 1 m, 95 turns of ferro nickel wire of 1.3 mm thickness, leaving 1 cm of separation between turns; the wire is 9.72 Ω / m and a length of 29 m is obtained. EXAMPLE 2 OF APPLICATION.

The first order differential equation, when a single phase capacitor of 30 uF is placed, the electrical resistance is 1 Ω, it has:

S + 33333 = 0

Claims

1. Electrical equipment that saves the energy generated by an electrical beam CHARACTERIZED BECAUSE the equipment is constructed by placing a capacitor 1 in parallel

30 μF, 500 KVAR, 6640 V, with a resistance 2 that has a value less than or equal to 33.67 Ω, and a conductive protective mesh 4 of copper insulated from ground with electrical insulators 6.

2. Electrical equipment that saves the energy generated by an electrical beam of Claim 1, CHARACTERIZED BECAUSE the equipment stores impulse currents from 200,000 A onwards and this energy is stored or dissipated in the equipment, in a maximum time of milliseconds.

3. The electrical equipment that stores the energy generated by an electrical beam of Claim 1, CHARACTERIZED BECAUSE the maximum value of voltage that the equipment endures in microseconds is 200,000 V.