SI9700277A - Switch-off mechanism of power protecting varistor energy conductor - Google Patents

Abstract

The present invention refers to a switch-off mechanism of power protecting varistor energy conductor. Proceeding on devices for protection of electric, electronic and telecommunication assemblies and devices from voltage overloading in the case of a stroke of lightning known up to the present, the invention is based upon the problems of: elimination of the emanation of heated gasses and moisture occurring on usual spark places, shortening the response time and elimination of high residual voltage, consideration of possibilities of permanent damages of certain crystal structure areas of varistors in the case of exceptionally powerful strokes of lightning, possibilities of deviations from tolerances of industrially manufactured varistors as well as assurance of possibilities of indication of damages or failures of certain components of the device according to the invention.

Description

Disconnecting mechanism for a power shielded varistor energy arrester

The present invention relates to a disconnect mechanism for a power shielded varistor energy arrester.

Based on the known devices for protection of electrical, electronic and telecommunication circuits and devices against voltage overloads in lightning strikes, the invention is based on the problem of eliminating the exhaust of heat gases and moisture present in normal sparks, shortening the response time and eliminating the high residual voltage, taking into account the possibility of permanent damage to certain areas of the crystal structure of varistoi by extremely heavy lightning strikes and the possibility of tolerance deviations of industrially produced varistoi, as well as to provide the possibility of indicating defects or failures of certain components of the device according to the invention.

Multiple varistor surge arresters with power up to 100 kA are known in the world for standard maximum current pulses of 8/20 form for energy supplies with a maximum voltage of 230/380 V at 50 Hz. They are all patented and have a unique way of contacting and disconnecting mechanisms.

The products of the manufacturers of Obo Betterman Germany, Phoenix Germany and Kleinhaus Germany are known.

For example, refer to European patent application no. EP 0716 493 A of the applicant Soule Materiel Electrique de Bigore France, which has a protective device for 70,000 A tip as well as Citel France. These products correspond in addition to the specified current drain when displaying the discharge of another standardized 8/20 current pulse of 10/350 ps capacity of about 7 to 9 kA, and therefore do not indicate this test pulse in the technical and commercial and patent documentation of varistor protection. They only provide information for measurements and discharge capabilities of an 8/20 ps current impulse. A protective device of this level is not sufficient in many very demanding cases. In this case - for the first time, the first time in a standardized current pulse, for example 8/20 ps, indicates an ascent up to 90% of the maximum value (peak or peak), and the second time is the time of fall to 50% of the maximum value or peak. top or. pulse tips. The first time represents the rate of rise of the head of the current pulse and causes large fields with electromagnetic induction. The second time is related to the length of the pulse and, above all, to its energy content.

Dehn & Sohne Germany with its design of VGA 280 protection device, also called Dehn-valve, with 100 kA 8/20 ps (4x25 kA 8/20) properties with three-phase protection and zero conductor together for 8/20 pulse, now gradually replacing it with more powerful lightning arresters in various combinations of protective devices. The varistors inside it were destroyed, because stronger lightning effects occurred than the arrester could withstand.

Other designs for direct lightning strikes are mainly used by sparks and a combination of protective sparks (70), with intermediate coil members (71) and varistor arrester (72) with lower drainage power up to a maximum of 40 kA 1 x.

The spark arrester (92) draws maximum lightning energy, but is slow. The bridging protection protects the next varistor arrester from high residual voltage, and the next varistor arrestor device (72) increases the response rate of the protective varistor assembly (94) and reduces the residual voltage at the output of the protective combination to a harmless level.

Various designs of protective varistor devices (1) for a maximum current of 150 kA and 5 varistos of standard dimensions (114), but special versions of drainage (115, 116) and connection terminals (110, 111, 111, 112), or (2) for four rectangular dimension varistions in 150 kA version (3) and five square varistions in 150 kA version (4) provided by the present invention have the ability to dissipate a maximum current form pulse

8/20 gs at 150 kA (5), as well as 15 kA (7) and in the version for a standardized lightning pulse of 10/350 gs (9). Figure 5.

In three phases and a neutral conductor (10), the devices of the present invention can collectively discharge currents of 60 kA (11) of 10/350 g of direct current into four parallel protection devices on conductors of the same power supply (Fl, F2, F3 and N) in one protection package struck by lightning. For three-phase star-bound conductors, the maximum discharge in the 45 kA direct lightning stroke is 10/350 gs.

The distribution of current must be uniform across all three phase conductors and the zero conductor.

Since the Lightning External Lightning Protection system drives away about 50% of the lightning to the ground, it requires the protective devices to discharge the remaining 50% of the lightning current. With new combinations, it is possible to defend objects, fixtures, machines, devices and personnel three-phase, even for the rare powerful direct high-altitude single-shot 90 kA and 120 kA 10/350 gs lightning.

This is higher than in the known protection devices, which operate only with high-speed metal oxide varistor protection, but less than in the combined protection versions, which are only needed for protection against extremely powerful lightning strikes.

Other original manufacturers of direct lightning and surge protector Dehn & Sohne Germany, Phoenix Germany and Obo Betterman Germany offer the already mentioned combinations of protective sparks (92) for direct lightning strikes, intermediate filter coils (93) and surge arrester arresters (94), which, in turn, greatly increases the cost of protecting the power supply altogether, since it must contain more protection devices for the same effect (70, 71, 72).

Here is an example of patent DE 4236584 Al in HO1T4 / 04, which deals with such protective combinations. This combined use of current arresters with sparks (70), intermediate members (71) and varistor surge arresters (72) is reasonable in the most extreme situations where one can expect from past statistics or measurements of extremely high lightning current surges, while protecting e.g. . only very sensitive devices which, by virtue of their importance, must never fail.

For spark gaps with a non-waterproof approach to spark surfaces, there is always the problem of heat exhaust. An additional problem is the humidity, which changes the conditions and causes the gas to hit the lightning. The possibility of explosions and injuries is greater. The problem is solved by a fast varistor assembly with larger rectangular dimensions varistoi (17), or by a set with five selected varistions of standard square dimensions (18), and a special housing design with synchronized exhaust chambers (Fig. 2c).

The disadvantage of the spark is also the relatively long response time and high residual tension. Therefore, a longer cascade of drainage and intermediate elements must be placed in the phase conductor or ground zero conductor at the spark. The first and second problems are solved with fast varistions. The residual voltage is much lower.

As the crystal structure of the varistors is slightly damaged in the event of an electric shock or there is an exceptional, extremely powerful lightning strike, the varistor may remain permanently damaged (21). In doing so, a short-circuit current can flow through the varistor, which greatly heats the ceramic structure and can cause fire and fire. An armor device (22) must be constructed to disconnect the damaged varistor group from the live conductors in accordance with the physical requirements at significantly higher discharge currents and existing standards. The mechanism has to meet several standards and is therefore extremely simplified.

[0003] The design of fault tripping (32) and nearby fault signaling (33) and remote fault signaling (34) are essential novelties of the present invention. Disconnections (32) are differentially displayed (33) on three windows (34) on the cover of the protection device (33a). The destruction of individual varistos or the destruction of subassemblies (36) is shown by three mutually independent metal flags (37, 38, 39) of disconnections and their disconnection from phase (40, 41, 42). The metallic flags (37, 38, 39) are painted on the later visible part with a correspondingly resistant red substance. When the flags are not unlocked, no red painted parts are visible and the window is dark, which means that the assembly is fully functional.

In the case of unilateral (43) or bilateral defect (44) of varistor subassemblies, the protective device of the invention may still operate at an otherwise lower but still satisfactory protective level (45), e.g. despite the injury to one of the varistor groups.

The remaining varistor protection can be 100 kA (46) or 70 kA (47) or 40 kA (48) for a single stroke of the maximum mentioned current of 8/20 ps.

It is appreciated that the present invention is not a combination of differential failure of a part of varistoi in double varistor subassemblies which are the subject of patent protection of Soule (80) from the aforementioned European patent application, or e.g. in triple varistor subassemblies, but for combinations of failures of damaged one single varistor subgroup at twice two good yet double (81) or for failure of one double at single and double still good (82), or failure of both double varistor subgroups at one more good single (83) or for complete failure (105).

Any failure must be remotely reported via the external terminal (49) on the housing of the varistor arrestor (50), although only a partial failure on the varistor arrestor itself has occurred. The failure of each varistor subgroup is shown separately on the housing (50) according to FIG. 4.

A failure of the entire power supply protection requires three or four conductor connections (51) and fault indications on the control panel (106).

It is necessary to provide 150 kA (8/20) current discharge on varistor surfaces (52), on spring contacts (53), on connection points on varistoy spring contacts of disconnections (107, 108, 109), on circuit inside (53) and against earth (54) with a mechanical structure (55-60) that does not allow a high-power varistor arrester (1) inside and (60) on the output terminals (60-63) against the shielded device, high residual voltages.

The internal inductances (64) must be minimal, which is the case for inductances (65) for even a power-shielded varistor device.

It is desirable to be bonded using large cross-sections of conductors (66), terminal blocks (67) and the related locking problem (68) to the 35 mm base-plate. This one has quite a few structural features (69-72).

Similar but different solutions are known from products such as automatic fuses and so-called φ-switches and various products, which are certified on a standard hat fastener.

In the case of protection against direct and indirect lightning strikes, however, these are additional requirements because rapid impulse current surges cause strong physical forces between the phase conductors and the varistor protection assembly and the mounting bracket. Therefore, in the product sub-assembly (68), a new embodiment of the closing mechanism of the attachment to the support hat strip is shown.

The problem of slow response and the excess residual voltage caused by lightning arresters with sparks is solved by rapid varistor arresters that react at least twenty times faster than sparks in less than 5 ps (69).

Because of the slow reaction, sparks allow a fairly large increase in the voltage at the arrester and the spark before they start operating and remove harmful currents and surges from the electrical conductors. These residual voltages are too high to speak of the harmlessness of their effect on the shielded device. Namely, we protect the most objects, persons and sensitive devices with integrated electronics, such as telephone electronic switchboards, computer centers, antenna towers, mobile telephony base stations, intensive care stations, television and radio centers, command and control units in hydro power plants, industry and more. as well as institutions, businesses and individuals and their equipment in an individual more exposed house.

The problem is solved because the residual overvoltages are lower than the varistor high-speed protection, and the assembly can be directly coupled to the shielded device without additional intermediate members, as is necessary for spark protection. An electrical schematic of this protection is shown schematically in FIG. 2 when displaying simple power protection. For three-phase zero-voltage power supply, the number of protective devices is reduced by 8 pieces (spark arrester (70), bridging coil (71), medium-voltage varistor arrester (72)

There is less design work, less space is required in electrical cabinets (73) and at protection sites, the installation is three times faster, and the cost of the complete protection components for the individual shielded power supply is lower.

The housings of the protected device (1) are two-part, from the bottom (74) and the cover (75). The housings must be made of high quality, highly fire resistant plastic (76). The problem requires a special design of plastic injection molding tools (77) to prevent material from twisting at very high pressures and operating temperatures. The housing also has a pre-vent for possible exhaust (110).

It is also possible to quickly replace the damaged varistor assembly as a whole (111). Partial replacements are generally not possible because the varistors would no longer be matched (112).

Varistor assemblies must be additionally marked (78) in order to avoid replacements. A complete mechanical and electrical disconnection (79) of the phase from the protective device (1) occurs if the impact is too large for each group. The problem is solved by the cross-sections of the connecting spring terminals (79b), which melt under extreme pressure under tremendous pressure. The circuit breaks and the arrester is disconnected.

The multi-purpose housing is designed with different inserts 13 and interchangeable parts; there are three different lower parts and two covers for different end products as well as many applications with electronic circuits.

Varistoi (85) and varistor groups (86) have been specially developed for simplified implementation. The circuit breaker circuit for remote fault indication (87) is triggered for any fault on varistor subassemblies. By means of a narrow transverse rectangular strip (88) projected (81) to the base contact, it captures semicircular motions of circuit breakers (22) which are for each or all three varistor subassemblies (80). With the spring (53), move the contact pen (89) of the microswitch (90) to another state (Fig. 6).

Compared to other known high current surge protection devices, ie 70 k A and 100 kA, having a separate base of at least three plastic parts and replaceable protection modules of at least three plastic parts and one fault indication, the housing of the device ( 50) according to the invention, characterized in that it is designed solely as a two-compartment, consisting of a cover (75) and a complex shaped bottom (74) with exhaust vents (110), comprising a triple transparent window (130) for differential indication mistakes.

All devices have different spring clips (125) for attachment to a standard 35 mm hat strip (131). In our case of very high currents, a metal spring clip is not the best fit. The coupling and uncoupling mechanism of the 150 kA protection device (133) of the varistor protection device (134) is designed according to the invention to provide, with its simple construction, material selection and satisfactory robustness, the shortest possible passage from the input terminals (132) to the inside of the protection device (60), thereby minimizing internal inductances (65), thereby reducing residual voltages that would occur inside and at the external terminal output terminals (63) of the protection device. The mechanism consists of standard connection terminals (132, 137) for small (25 mm ² ) and large cross sections (35 mm ² ) of connected conductors and flush internal terminal for bus (138) and is characterized by a specially adapted connection to varistor assembly 122, large rectangular shaped flat contact contact for fitting to varistor ceramic double-silvered surface 113 and 116, after connection for fusible low-temperature solder (135), passage through two or three spring-specific disconnect contacts (107, 108, 109), which are specifically adapted (136) for the transmission of large drainage currents and possible self-protective melting of the metal strip conductors (137) in the event of excessive shocks when much slower mains fuses are melted. From there, a group contact is made to the outgoing inward grounding clamp (139) and the outlet grounding clamp (137), which leads the surplus of impacts towards the earth.

In the implementation of the present invention, we have used a new construction of varistor connectors (110, 111), characterized in that the external connectors - e.g. 110, 111 - on either side of the varisto angle with a smaller distance of twice 15 mm (140) from the varisto angle. This enables the specific mechanical construction of the power varistor arrester, which is also the subject of patent protection within the scope of the present invention.

Another feature of the invention is a rectangular varistor (100), designed to have an approximately 25% larger drainage surface, and provided with two rectangular terminal plates (116) comprising terminal contacts (112, 113) spaced at a smaller angle. from twice 15 mm from angle (141).

A simple failure mechanism, signaling and differential fault signaling and remote fault signaling were also implemented. Permanent failure of a varistoi or varistor subassembly requires the required standards to achieve disconnection from an active phase or zero conductor.

According to the invention, the disconnect mechanism (140) operates as follows: Varistor 117 is heated on the varistor surface (52) above the temperature of the solder joint (135) of the spring contact (53) and passes (143) to the disconnected state (145) . The solution according to the invention is characterized by the fact that there are three disconnect contacts (107, 108, 109) of strip form (146), selected and exchanged thicknesses 107 for the required currents between 100 kA and 150 kA and are spring only (147) and are as soon as possible electrically connected to the common contact surface of the circuit breakers (145), which is bound to the external connections. The tips of the contact contact springs (107, 108, 109) are colored with a high resistance red mass to indicate the failure (148). A red indication of failure 120 appears in the transparent window 121, which is previously dark. The failure display can thus be differential (149), as shown in Figure 4 for one possible example and schematically shown in Figure 7a, 82a, 82b, 83 and 43.

The simple remote signaling mechanism (149) according to the invention is designed as follows: After disconnecting one or more spring disconnect contacts (107, 108 or 109), the disconnected spring strip metal contact strikes - e.g. 108 - into the hollow (81) transverse filler strip (88) on the contact pen (89) of the microswitch (90). The microswitch (90) switches to voltage and triggers remote fault signaling (Figures 6 and 8).

Due to the high current surges, a high physical force is applied to the spring latch, which holds the varistor power arrester 1 to the hat standard fastening bar. The spring snap 125 according to the invention has a normal pull-out part with a screwdriver 126 and a supplementary pull-out part 152, as well as a tilt for the baseboard abutment 153 and specially marked parts as follows, Very strong and specially shaped spring knee 127 with lateral reinforcement 150, sliding nipple 128 and a certain raster 151 between the two limb arms.

Claims (7)

PATENT APPLICATIONS 1 A disconnect mechanism for a power-shielded varistor energy arrester, characterized in that the housing (50) of the device is only two-part and consists of a lid (75) and a complex molded bottom (74) with pre-chambers for exhaust (110) and comprises a triple transparent window (1). 130) for differential fault indication, with all devices having different spring clips (125), having a hinged bar (131) for standard 35 mm, and not having metal spring snaps in the case of very high currents. 2. Mechanism according to claim 1, characterized in that by its simple construction the choice of materials and satisfactory robustness enables the shortest passage from the input terminals (132) to the inside of the protective device (60), thereby reducing the internal inductances (65) to the minimum possible, thereby reducing the residual stresses that would occur inside and on the external terminal output terminals (63) of the protection device, the mechanism consisting of terminal standard terminals (132, 137) for small (25 mm ² ) and large cross sections (35 mm ² ) of connected conductors and flush inner terminals for guide (138) and designed with a specially adapted connection to the varistor assembly (122), a large rectangular shaped flat contact contact for fitting to the varistor ceramic double-silvered surface (113) and (116) ), fusible low-degree solder connection (135), passage through two or three spring disconnect contacts (107, 108, 109) which are adapted or. specially dimensioned (136) for the transmission of large drainage currents and possible self-protective melting of the metal strip conductors (137) in the event of excessive shock when the much slower mains fuses are melted, and further from there group contact is made to the outgoing inward earth clamp (139) ) and an output grounding clamp (137) that guides the surplus hits towards the ground. 3. Mechanism according to claim 1, characterized in that the outer connections (eg 110, 111) are arranged on both sides in a varisto angle with a smaller distance of twice 15 mm (140) from the varisto angle, thus allowing specific mechanical construction power varistor arrester. The mechanism according to claim 1, characterized in that the rectangular varistor (100) has a 25% larger drainage surface and is provided with two rectangular terminal plates (116) having contact contacts (112, 113) spaced at a smaller angle a distance of twice 15 mm from the angle (141). A mechanism according to claim 1, characterized in that it comprises a fault signaling and tripping assembly, namely fault signaling and / or differential fault signaling and / or remote fault signaling, with three tripping contacts (107, 108, 109), strip-shaped (146), selected and alternated thicknesses (107) and are spring-only (147) and are electrically connected to the common contact surface of the circuit breakers (145) as soon as possible, which is bound to the external connections, the tips of the contact contact springs ( 107, 108, 109) are colored by a high-pressure red mass for failure indication (148), with the red fault indication 120 appearing in the transparent window 121, which is dark beforehand, and the failure display may thus be differential (149 ). 6. Mechanism according to claim 1, characterized in that after disconnecting one or more spring disconnect contacts (107, 108 or 109), the disconnected spring contact (eg 108) strikes a hollow (81) transverse complementary contact strip (88) at the contact pen (89) of microswitch (90), whereby the microswitch (90) switches to voltage and triggers remote fault signaling. A mechanism according to claim 1, characterized in that the spring latch (125) comprises a normal pull-out part (126) with a screwdriver and a pull-out part (152), an inclination for the baseboard support (153) and specifically marked parts, namely, a strong and specially shaped suspension knee (127) with lateral reinforcement (150), a sliding nipple (128) and a fixed raster (151) between the two arms of the knees.