MXPA96004530A - Ventilation system for mechanismode environment resistant control plant - Google Patents

Abstract

The present invention relates to a ventilation system for an arc resistant enclosure for electrical components, said enclosure comprising: compartments for housing said electrical components, and an internal arc chamber, said arc chamber providing a path for releasing from said enclosure the pressure and hot gases produced by an electrical arc fault associated with an electrical component in one of said compartments, said arc chamber comprising: a first section for providing an exit path towards the upper part of said enclosure; section to allow a portion of said arc chamber located under one of said compartments, said second section communicating with the first section by means of which pressure and hot gases produced within a compartment within which a failure occurs. of electric arc are released controllably from said recint or by means of the arc chamber, said ventilation system comprising: vent hole means for, in a first position, allowing normal convection cooling within at least one of said compartments by means of which the heated air it can flow between said at least one compartment and the arc chamber and, in a second position, prevent the pressure and hot gases from flowing from said arc chamber into said at least one compartment.

Description

VENTILATION SYSTEM FOR ARC RESISTANT CONTROL MECHANISM ENCLOSURE FIELD OF THE INVENTION The present invention relates generally to the field of electrical power distribution equipment, such as the medium voltage control mechanism and, more particularly, to an arc-resistant enclosure for housing the control mechanism - medium voltage and a ventilation system of the same. BACKGROUND OF THE INVENTION The arc-resistant control mechanism enclosures must be designed to withstand the pressures and temperatures of the gases associated with an internal arcing fault. Such enclosures are designed to direct pressure and hot arc gases away from personnel and therefore increase safety. Prior to the present invention, the method for increasing the safety of the control mechanism most commonly employed through an arc-resistant construction was to provide a vent hole by vertical suction, direct from each compartment to the top of the control mechanism enclosure. One problem with this practice is that it prevents the use of vertically stacked dispositions (eg, 2-high switch, 1-high switch, with voltage transformer cabinets), which are commonly used in the North American market. control mechanisms. This limitation, that is, the impediment in the use of vertically stacked dispositions, limits commercial acceptance of arc-resistant construction in the United States. Other control mechanism designs of the prior art have used external arc chambers. A problem with external arc cameras is that they limit the number and type of control mechanism configurations that can be deployed within a given volume. In addition, certain classes of arc-resistant control mechanisms also require that the pressure and hot arc gases not enter any of the adjacent enclosures. This poses a problem for venting the higher capacity compartments mounted below, since there may be a requirement for a natural air circulation ventilation path while preventing any pressure or gases from entering those ventilated compartments. Typically, any ventilation system of this type must also allow adequate ventilation of arc gases if they originated in the ventilated compartment. The above information relating to the present invention can be found in the following publications: "The Safety Benefits of Are Resistant Metalclad Medium Voltage Switchgear," 94-CH3451-2 / 94 / 0000-0309, 1994 IEEE; "Procedure for Testing the Resistance of Metalclad Switchgear Under Conditions of Arcing Due to Conditions of Internal Fault," EEMAC Standard G14-1, 1987 (this is the test standard used in North America; ANSI does not currently refer to this publication, although has established a working committee ANSI); and "Improved Switchgear Safety Through Are Resistant Construction," by Paul Thompson and E. John Saleeby, 1994 (presented at the "Electric Utility Conference" of 1994). BRIEF DESCRIPTION OF THE INVENTION Accordingly, an object of the present invention is to provide an enclosure for improved arc-resistant control mechanism. A more specific object of the present invention is to provide a cost-effective means for collecting and channeling the pressure and hot arc gases from the lower compartments and safely channeling those pressures and gases through the control mechanism enclosure . An additional objective is to provide a ventilation system that provides natural ventilation while preventing any pressures and arc gases entering from the lower ventilated compartment and allowing adequate ventilation of the pressure and arc gases if they originated in the ventilated compartment. in a natural way The present invention can be advantageously employed in association with, and as an improvement of the invention claimed in the co-pending application of Serial No. (in the case of proxy ABMS-0046 / PDDMS94-02), entitled "Arc-Resistant Switchgear Enclosure , "presented on the same date as this.

The present invention achieves these objectives by employing, in the preferred embodiments, a series of compartments or modules that are placed in various configurations. According to the invention, an internal arc chamber is formed by assembling the modules and creating a gap within the center of the control mechanism enclosure. Since multiple compartments for a control mechanism enclosure are connected or assembled, an arc chamber is created, having horizontal and vertical sections within the enclosure of the control mechanism. Upon initiation of an arc fault within a particular compartment, a relief cover or cover will be opened for that particular compartment, venting the gases within the internal arc chamber or directly through the upper part of the enclosure (depending on the location of the compartment). The pressure and gases that are channeled into the inner arc chamber flow through the arc chamber until a section of the arc chamber is reached within the control mechanism enclosure that includes an exit path to the superior of the enclosure. This pressure and hot gases are then channeled through the outlet path and safely out of the control mechanism enclosure. The arrangement is such that pressure and hot gases produced within a compartment in which an electric arc fault occurs are released in a controlled manner from the top of the control mechanism enclosure and are prevented from entering the compartment within which an electric arc fault has not occurred. A ventilation system according to the present invention comprises vent hole means that allow normal convection cooling within at least one compartment by means of which the heated air can flow between the compartment and the arc chamber and which avoids that pressure and hot gases flow from the arc chamber inside that compartment. Preferably, the vent hole means comprises a plurality of ventilation slots placed in the relief cover or cover for that compartment to direct the heated air out of that compartment and into the arc chamber and, pivotable vent covers for Cover and discover the grooves. The vent covers automatically and quickly close the slots in case the pressure and gases generated by an arc fault within another compartment are present in the arc chamber. In summary, the present invention employs an integrated internal arc chamber that contains and controls the heat forces and related forces, i.e., the pressure created by hot gases and other particles, associated with an internal arc fault in a mechanism of control of medium voltage and other types. The invention minimizes the risk of damage to personnel in the vicinity of the control mechanism enclosure and also provides a ventilation system for ventilating the compartments mounted further down so that a natural air circulation path is provided as long as , when required, prevent any pressure and hot gases from entering those ventilated compartments. Other characteristics of the invention are described below. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a diagrammatic isometric view of a control mechanism enclosure containing an internal arc chamber according to the present invention; Figure 2 is a diagrammatic cross-sectional view taken along line 2-2 of Fig. 1; Figure 3 is a diagrammatic cross-sectional view of a control mechanism enclosure configuration in accordance with the present invention; Figure 4 is a diagrammatic cross-sectional view of another control mechanism enclosure configuration according to the present invention; Figure 5 is a diagrammatic cross-sectional view taken along line 5-5 of Figure 1: Figure 6 is a diagrammatic cross-sectional view of another control mechanism enclosure configuration according to the present invention which also illustrates an aspect of the slot and cover ventilation system of the preferred embodiment of the present invention; Figure 7 is a diagrammatic cross-sectional view of another control mechanism enclosure configuration in accordance with the present invention; Figure 8 is a diagrammatic cross-sectional view taken along line 8-8 of Fig. 6; Figure 9 is a diagrammatic cross-sectional view taken along line 9-9 of Figure 6; and Figure 10 is a diagrammatic isometric view of the slot and lid vent system depicted in Figure 6. DETAILED DESCRIPTION OF THE PREFERRED MODALITIES The present invention provides an integrated internal arc chamber particularly suitable for releasing the pressure in a controlled and safe manner. and hot arc gases from the lower compartments of a control mechanism enclosure. In the presently preferred embodiments, this arc chamber comprises a horizontal component or section and a vertical component or section, and operates by directing the pressure and hot gases produced within a compartment (s) by an associated arc fault. with an electrical component in the compartment (s) outside the relief cover on the roof or top of the control mechanism enclosure. In addition, a series of ventilation slots may be added to the arch relief cover on the lower compartment (s) to direct the ventilation air to the arc chamber. This ventilation system, which includes one or more slatted tops, is illustrated in Figures 6, 8, 9 and 10 and is described below following the description of the inner arc chamber, which is described below and illustrated in FIGS. Figs. 1-7. Referring now to the drawings in which like reference numbers indicate similar parts in the different views, Figs. 1-7 illustrate various configurations of metalized arc-resistant control mechanisms in accordance with the present invention. Fig. 1 illustrates a diagrammatic isometric view of a control mechanism enclosure generally shown as 100. As can be seen from Figs. 1 and 2, with Fig. 2, for example, illustrating a cross-sectional view of a 1-high breaker configuration 1200A / 2000A, a circuit breaker compartment 10 is placed below a compartment 12 (Fig. 2). ) for low voltage equipment and adjacent to a cable compartment 14 and a bus bar compartment 24. An arc chamber 30 is positioned as shown above compartment 10 and to the right of compartment 24. Each of the compartments 10 and 24 have an opening 102. The arc chamber 30 and hinged covers 40, 42 allow pressure and arc gases to escape safely from any of the compartments 10 and 24, and are vented through the roof or top of enclosure 100. This allows pressure and gases to be released without the risk of harm to personnel who must be working near the control mechanism. Fig. 3 illustrates a cross-sectional view of a configuration including a switch compartment 10 of 1200A directly below a low-voltage switch compartment 12 'and an internal arc chamber 30'. In this configuration, the low voltage compartment 12 'and the internal arc chamber 30' have a shorter cross section to provide space for a Control Power Transformer with fuse or compartment TEC 16. A fuse 25 is shown in diagrammatic form above the TEC. The arc chamber 30 'includes a horizontal section and a vertical section ventilated through the roof of the enclosure. A vertical section can be better seen in Figure 2. The configurations illustrated in Figs. 3, 4, 6 and 7 are similar to those of Figures 1, 2 and 5. FIG. 4 illustrates a cross-sectional view of a switch configuration of 1200A with a single voltage transformer unit configuration, including a low voltage compartment 12"and internal arc chamber 30" intermediate height and a voltage transformer compartment 18. Figure 5 illustrates a configuration that includes a switch compartment 10 of 1200A and two voltage transformer compartments 18, twenty; Figure 6 illustrates a cross-sectional view of a configuration of 1- high 2000A / 3000A including orifices or spline slots 50 (best seen in Fig.10); and Figure 7 depicts a cross-sectional view of a 2-high configuration 1200A. In a specific execution of the invention, all the different modules are 91.44 cm wide and 48.26, 96.52 or 144.78 cm high. The depth of the different control mechanism modules is typically 101.60 cm and, to accommodate the internal arc chamber 30, 30 ', 30", as shown, the depth of the low voltage modules is approximately half that of the the depth of the three modules The different configurations also include one or more external covers 40 for venting the pressure and the hot gases produced when an internal arc occurs.The inner caps 42 are also provided to allow such hot gases to escape from the compartments external to the inner arc chamber 30. In configurations in which the inner arc chamber 30 'does not have a direct path to the roof or upper part of the control mechanism enclosure 100 (such as those illustrated in Figs. , 4, 5 and 7), the internal arc chamber includes a portion (a horizontal section) below one of the compartments that communicates with a vertical section. l that leads to the upper part or ceiling of the enclosure of the control mechanism 100. From the foregoing those skilled in the art will understand that while the preferred embodiments of the invention have been described and illustrated in the various Figures comprising a series of modular compartments placed in different configurations and thus forming an internal arc chamber as described, the internal arc chamber can also be constructed within an integrated frame design by bolting, welding or other metal sheet holding or another suitable barrier material within an integrated frame structure to form the internal arc chamber. The pressure relief caps or covers 40 could be formed in a similar manner as a part of the frame, integrated to allow hot gases to enter the internal arc chamber. An essential aspect of the present invention is that several electrical components that house compartments have openings with cover means covering the opening of the component which is associated during normal operation with an electrical component and when an arc fault occurs in a compartment with an electrical component. the one that is not associated. Upon the occurrence of an arc fault within one or more of the compartments, the cover means discover the opening of a compartment in which an arc fault occurs to allow pressure and gases to flow from a compartment in which an arc fault occurs within the arc chamber and flows through the arc chamber until a section of the arc chamber within the enclosure of the control mechanism is reached including an exit path to the top of the enclosure of the control mechanism so the pressure and gases are controllably released from the control mechanism enclosure. As mentioned above, a plurality or plurality of ventilation slots 50 may be added to the arc relief cover or cover on the lower compartment (s) to allow normal convection cooling and to direct the heated air outside the lower compartment (s) to the arc chamber. This aspect of the preferred modalities is claimed in the co-pending application of no. serial number (case number of the attorney ABMS-0048 / TMSSA95-02), entitled "Ventilation Systems for Are Resistant Switchgear Enclosure," filed on the same date as this one. As shown in Figs. 6 and 8-10, a plurality of cap spring members 108 hold the caps 60 in a substantially vertical first position., the caps 60 have a hinged pivot point 110 at the edge of the slots 50. The caps 60 can be easily released from the slight pressure exerted by the spring members 108 to quickly fall to a second horizontal position to close the slots 50 in case of pressure and arc gases, such as pressure and hot gases generated by an arc fault within another compartment, which are present in the arc chamber. Since this cap and slot system can be added directly to the arc relief cap of the lower compartment (s), it is not necessary to deteriorate the overpressure protection. In other words, the caps 60 will close automatically when the pressure within the internal arc chamber 30, 30 ', 30"increases due to an arc fault within one of the other compartments. of the preferred embodiments limits the scope of protection of the following claims, Therefore, for example, except when expressly limited in that way, the following claims are not limited to processes that employ any number, configuration or particular form of compartments of control mechanism.

Claims (6)

1. CLAIMS 1. A ventilation system for an arc resistant enclosure for electrical components, said enclosure comprising: compartments for housing said electrical components; and an internal arc chamber, said arc chamber providing a path for releasing from said enclosure the pressure and hot gases produced by an electrical arc fault associated with an electrical component in one of said compartments; said arc chamber comprising: a first section for providing an exit path towards the top of said enclosure; and a second section for allowing a portion of said arc chamber to be located below one of said compartments, said second section communicating with the first section by means of which pressure and hot gases produced within a compartment within the which occurs an electric arc fault is controllably released from said enclosure by means of the arc chamber, said ventilation system comprising: vent hole means for, in a first position, allow the normal convection cooling within at least one of said compartments by means of which the heated air can flow between said at least one compartment and the arc chamber and, in a second position, prevent pressure and hot gases from flowing from said arc chamber within said chamber. at least one compartment.
2. 2. A ventilation system as cited in the claim 1, wherein said vent hole means in the first position also allows the pressure and gases to flow from said at least one compartment into the arc chamber when an arc fault occurs in said at least one chamber.
3. 3. A ventilation system as cited in the claim 2, wherein said compartments have an opening for allowing pressure and gases to flow therefrom into the arc chamber and, further comprises the cover means for each of said openings and said vent hole means comprise a plurality of ventilation slots placed in the cover means of said at least one pivotable ventilation compartment and covers to cover and uncover said slots.
4. 4. A ventilation system as cited in the claim 3, further comprising means for holding said pivotable vent caps in said first position and for allowing said pivotable vent caps to move to the second position at the occurrence of the pressure and gases generated by an arc fault within another compartment that is present in the arc chamber.
5. A ventilation system as recited in claim 4, wherein said means comprises a plurality of spring members, each of said spring members being constructed and positioned to support a pivotable vent cover in said first position and for Release it to the occurrence of pressure and gases that are present in the arc chamber.
6. 6. A ventilation system for an arc-resistant enclosure for electrical components, said arc-resistant enclosure comprising: a plurality of compartments for housing the electrical components, each of said compartments housing one or more said electrical components, said plurality of compartments being positioned to form an internal arc chamber to provide a path for releasing from said enclosure the pressure and hot gases produced by an electrical arc fault associated with an electrical component in at least one of said compartments; each of said compartments having an opening for allowing pressure and gases to flow therefrom into the arc chamber and having hinged cover means for each of said openings; said hinged cover means covering the opening with which they are associated during normal operation and when an arc fault occurs in a compartment with which they are not associated and, the occurrence of an arc fault within one or more of said compartments, discover the opening of the compartment in which an arc fault occurs to allow pressure and gases to flow from a compartment in which an arc fault occurs in the arc chamber; said arc chamber comprising a first vertical section that provides an exit path toward the top of said enclosure; and a second horizontal section for allowing a portion of the arc chamber to be positioned below at least one of said compartments, said second section being adjacent to and in communication with the first vertical section, the arrangement being such that the pressure and Hot gases produced within a compartment within which an electrical arc fault occurs are released in a controllable manner from the top of said enclosure and prevented from entering a compartment in which arc failure has not occurred, said arc system. vent comprising: vent hole means comprising a plurality of ventilation slots positioned in at least one of said cover means and a plurality of pivotable vent covers mounted on said at least one cover means for covering and discovering said venting means; slots, slots allowing convection cooling inside at least one of d Said compartments by means of which the heated air can flow between said at least one compartment and said arc chamber when the ventilation covers discover said slots, the covers, when covering the slots, prevent the pressure and hot gases from flowing from the arc chamber in said at least one compartment. SUMMARY OF THE DESCRIPTION An improved arc-resistant control mechanism enclosure is described. The described arc-resistant control mechanism enclosure provides cost-effective means for collecting and channeling hot pressure and exhaust gases from the lower compartments and safely venting those gases through the control mechanism enclosure. In the preferred embodiments, an internal arc chamber is formed by assembling modules and creating a gap within the center of the control mechanism enclosure. Since multiple compartments or modules are connected to a control mechanism enclosure, an arc chamber is created within the enclosure. Upon initiation of an arc fault within a particular compartment, a relief cover or cover for that particular compartment is opened to channel pressure and gases into the internal arc chamber or directly through the upper part of the enclosure . The pressure and gases vented inward from the inner arc chamber flow horizontally through the arc chamber until they reach a path towards the top of the control mechanism enclosure. These pressures and gases are then channeled upwards and safely out of the control mechanism enclosure. Also described is a ventilation system for an arc-resistant control mechanism enclosure that provides natural ventilation while preventing any arc gases from entering the compartment (s) allowing adequate ventilation of the pressure and arc gases if originated in the ventilated compartment (s).