HK1180451B - Excess voltage circuit-breaker with a rotational disc and an electronic assembly to improve operation reliability - Google Patents

Abstract

The excess voltage circuit breaker with a rotational disc and an electronic assembly to improve operation liability solves a problem of construction of electronic and mechanical disconnection of a connection terminal of an excess voltage protective element based on e. g. spark gaps, varistors, semi-conductors like diodes, thyristors and similar elements in case of occurrence of electric arc and electric thermal overloads. The essence of the excess voltage circuit breaker of the invention lies in an electronic assembly of a component (2) which comprises a resistor (PTC) with positive thermal coefficient which is connected in parallel to a gas circuit breaker (GDT). The resistor (PTC) is a resistor (2d) in the embodiment. The circuit breaker (GDT) comprises two gas circuit breakers (2b and 2c), wherein the common exit point of the resistor (2d) and the circuit breaker (GDV) is via thermal member (V), which is simultaneously a connection electrode (2f) arranged on a varistor (2a) body. The electronic assembly of the component (2) functions in a way that in case of rapid transition events a branch with the gas circuit breaker (GDT) is operable and in case of sporadically increased voltages the branch via the resistor (2d) is operable. The resistor (2d) with positive thermal coefficient limits the current through the varistor (2a). The varistor (2a) in low ohmic state allows high current to run through the varistor (2a) thus enabling the operation of external over-current protection. The movement of the connection electrode (2f) triggers the movement of the rotational disc (4), the spring (5), the latching plate (6) which changes the state of the indicator (8).

Description

Overvoltage circuit breaker with a rotary disk for increasing operational reliability and electronic assembly

Technical Field

The invention relates to an overvoltage protection device for protecting electrical and electronic devices against arcing and electrical thermal overloads of varistors, which are caused by electric shocks and transition phenomena in low-voltage networks, which are reflected in an increased voltage.

Technical problem

The technical problem addressed by the present invention is a constructive solution to the mechanical disconnection of the terminal clamps of overvoltage protection elements based on, for example, spark gaps, varistors, semiconductors like diodes, thyristors and similar elements in the case of electrical arcs and electrical thermal overloads. This solution must provide a fast response to sudden voltage phenomena, wherein remote signaling of the fault and timely reporting of the location of the fault are also important. A fast switching-off operation is important because of the possibility of a long-term increased voltage, which may occur for hours or even days. This can lead to damage of the overvoltage circuit breaker, which in the worst case can cause a fire.

Prior Art

An overvoltage circuit breaker is an electrical device for limiting overvoltage in an electrical energy system. The various overpressures differ in their duration and are therefore divided into two groups: the first group is transient voltages caused by switching operations and overvoltages caused by atmospheric discharges, and the second group is so-called temporary overvoltages caused by short-circuit-like defects in the grid, high-voltage system circuits, losses of neutral conductors, unstable grids, etc.

Known components of overvoltage breakers are, for example, spark gaps, varistors and diodes, to mention just those which are most widely used. They have in common that they switch to a conductive state when the voltage increases and release the increased voltage in a direction towards ground through the protected conductor.

In particular, problems are encountered when long-term increased voltages of several hours or even days occur, which can lead to damage of the overvoltage circuit breaker and in the worst case to a fire. Several ways of addressing these situations or problems are known and all share a common property, namely: they transition to the on state using the components described above. After the transition to the conducting state, the overvoltage disconnector disconnects the overvoltage protection or differential current switch from the power network or from a device cooperating therewith, which detects an increasing current in the direction towards the protected conductor. These conventional solutions may be external, but there are still so-called internal solutions in which, further, the protective element is integrated in the monolithic axle housing. Several problems arise in this connection, namely: overvoltage breakers do not retain the attributes they had prior to the added solution.

Several solutions are available and solve the problem of arcing in the varistor and electrical thermal overload.

A solution is known from patent US6430019, in which the generation of arcs at the critical temperature of the varistor is prevented by a barrier which gradually moves into the gap between the disconnected electrode and the varistor body and separates the overheated varistor body from the connection electrode, thus preventing arcs.

The solution known from DE102007051854 is a known disconnection device based on at least one overvoltage arrester, for example a varistor, and a disconnection device for disconnecting the overvoltage disconnection device from the power grid. One drawback of this solution is that: when the voltage across the varistor increases, reliable disconnection in all modes of varistor overload cannot be ensured. In the event that the varistor would enter a short circuit condition before performing the thermal disconnect function, the series overvoltage protection operation would likely be limited or disabled.

Patent application DE102008013448 describes a circuit breaker which is connected in parallel with the device it protects and which opens when a preset separation distance of the circuit breaker is reached.

The known solutions described do not provide an optimal solution to the problem relating to the occurrence of an arc in an overvoltage protection device having a plurality of varistors. The problem of preventing leakage currents, from which the electrical thermal overload of the individual varistors is determined, and in the event of insufficient disconnection, the arc can also be increased to a destructive magnitude, remains unsolved.

Solution to the technical problem

The essential point of an overvoltage circuit breaker with a rotary disk for increasing operational reliability and an electronic assembly is that: the rotating disc of the varistor is electronically triggered immediately after detecting the voltage increase on the varistor by means of a blow-out switch and/or a resistor with positive thermal characteristics aligned with the varistor. As the flux of the break electrode starts to melt, the spring moves the rotating disc under the break electrode, which may interrupt a possible arc between the previously unprotected surface of the varistor and the break electrode. The rotary disk is designed in such a way that: which extends to the distance specified by the standard. The locking plate of the indicator releases the indicator, which moves towards the gap on the housing and thus clearly indicates that the varistor is disconnected from the active components of the network.

Drawings

An overvoltage circuit breaker with a rotary disk for improved operational reliability and an electronic assembly according to the invention will now be described in more detail by means of the accompanying drawings, in which:

fig. 1 shows the assembly of an overvoltage circuit breaker according to the invention;

fig. 1a shows the assembly of an overvoltage circuit breaker according to the invention;

FIG. 2 is a rotating disk;

fig. 3 shows an electronic assembly 2 according to the invention;

FIG. 4 is a diagrammatic view of an electronic assembly of the present invention;

fig. 5 is a diagram of an electronic assembly 2 according to variant II.

Detailed description of the invention

The overvoltage circuit breaker of the invention comprises a housing 1 with an assembly 2, which assembly 2 has a varistor 2a, puffer breakers 2b and 2c and a varistor 2d, which varistor 2d has positive thermal properties. The varistor 2a has first and second connection electrodes 2e and 2 f. The frame 2g serves as a first connecting electrode 2e at the same time, which protrudes from the case 1. The support 3 for the rotating disc 4 is arranged on the frame 2g of the assembly 2. The bracket 3 has a shallow circular recess 3a, the circular recess 3a having a male cylindrical appendage 3b, the male cylindrical appendage 3b having a slot 3c in the middle. An elliptical opening 3d is provided at the bottom of the circular recess 3 a. The rotary disc 4 is fitted centrally with a circular hole 4a, which circular hole 4a is surrounded by a lower ring 4b, which lower ring 4b has a split 4b ', which split 4 b' is immediately adjacent to a first cylindrical attachment 4c in the rotary disc 4. In the rotary disc 4, on the opposite side of the first cylindrical appendage 4c, there is an opening 4d, which starts at the second cylindrical appendage 4 e. The ring 4b has the same height as the spring 5, said spring 5 being designed in such a way that it starts with a first straight portion 5a, which first straight portion 5a is straight and forms an uppercase letter D with the first semicircular bend. The spring 5 is wound around this part in such a way that: the second part of the spring 5 in the line of the first straight part 5a is also straight and ends in a semi-circular part 5b, which semi-circular part 5b forms a mirror image of the capital letter J together with a second straight part 5 c.

The latch plate 6 has an oblong opening 6a and a circular opening 6 b. The plate 6 has protrusions 6c at opposite sides of the opening 6 a. Behind the short straight part behind the protrusion 6c there is a protrusion 6 d. The circuit breaker is closed inside a casing 1 with a cover 7, the cover 7 following the shape of the bottom of the casing 1. The cover 7 has two plugs 7a for closing the components of the overvoltage protection circuit breaker according to the invention in the housing 1.

The case 1 of the overvoltage circuit breaker encloses a component 2 therein, which component 2 comprises a body of a varistor 2a having a flat shape, preferably square or oval. The support 3 of the rotating disc 4 is arranged on the frame 2g of the assembly 2 in such a way that: the connecting portion of the frame 2g is the first connecting electrode 2e of the varistor 2 a. A second connection electrode 2f is arranged on the body of the varistor 2a through the oblong opening 3d, said second connection electrode 2f being shaped in such a way that: which has a curved portion 2 f' in contact with the varistor 2 a. A temperature sensitive flux is used to solder the contact. The second portion 2f "is straight and is bent in the portion 2 f'" in a parallel manner to the first connection electrode 2 e. The size and shape of the oblong opening 3d makes it easy to arrange the second connection electrode 2f of the varistor 2a and to place it at an angular distance from the starting position of the rotary disk 4, so that the rotary disk 4 covers the oblong opening 3d in its end position after having rotated around the convex cylindrical appendage 3 b. The second connecting electrode 2f is arranged on the piezoresistor 2a through the elliptical opening 3d by means of temperature-sensitive flux and is fixed on the upper side of the body of the piezoresistor 2 a. The second connection electrode 2f is held at a position: the rotary disc 4 is in its starting position and the spring 5 is in a biased state.

The rotary disc 4 pivots in the shallow recess 3a and passes through the circular hole 4a to the male cylindrical appendage 3b of the support 3. In the centre of the shallow recess 3a delimited by the lower circular ring 4b there is a spring 5, the first straight portion 5a of which 5 is blocked in a slot 3c on the male cylindrical appendage 3 b. After the second connection electrode 2f has passed through the oblong opening 3d in the disc 3 and the opening 4d, a second part of the spring 5 with a semi-circular portion 5b is arranged around the second cylindrical appendage 4 e. The circular opening 6b of the locking plate 6 is inserted into the cylindrical appendage 3e of the support 3 and at the same time also into the oblong opening 6a, reaching the second cylindrical appendage 4e of the rotating disk 4. The protrusion 6d is inserted into the socket 8a of the indicator 8 which signals the start condition.

When the body of the varistor 2a heats up sharply due to a surge in voltage and current and an increase in current therethrough, the temperature sensitive flux connecting the second connection electrode 2f to the body of the varistor 2a melts. Thus, the second connection electrode 2f is free to move through the oblong opening 3d in the holder 3 to the stress-free position and thus release the rotating disc 4 which is now in the initial position. The force of the spring 5 acts on the rotary disk 4 and the latter turns the convex cylindrical appendage 3b to the end position in which the rotary disk 4 covers the oblong opening 3d in its support 3. The rotating disk 4 moves at a high angular velocity from one end position to the other end position under the influence of the elastic force of the coil spring 5, and covers the elliptical opening 3d in the bracket 3, thereby preventing the generation of an arc. The movement of the rotating disc 4 triggers the latch plate 6, which by means of its attachment 6d moves the indicator 8 towards the opening of the housing 1 a.

Fig. 4 shows a block diagram of an assembly 2 with a PTC resistor and a GDT puffer breaker connected in parallel and a MOV varistor connected in series between the respective terminals of the first and second connection electrodes 2e and 2 f. The electronic assembly of the assembly 2 comprises a resistor 2d with a positive thermal coefficient, which resistor 2d is connected in parallel with the GDT puffer breaker. In the present embodiment, the PTC resistor is the resistor 2 d. The GDT circuit breaker in the present embodiment includes puffer breakers 2b and 2 c. The common run-out point of the resistor 2d and the GDT breaker passes through a thermal component V, which is also a second connecting electrode 2f provided on the body of the thermistor 2 a. The electronic assembly of the assembly 2 operates in a so-called identification mode, which indicates that the branch of the GDT puffer breaker is operational in the event of a rapid transition, and that the branch via the resistor 2d is operational in the event of an occasional voltage increase. The essence of the function of the resistor 2d with a positive thermal coefficient is to limit the current through the varistor 2a when the applied voltage on each connection terminal exceeds the voltage threshold of the varistor 2 a. This is a key difference compared to other manufacturing: the varistor 2a is shifted to a low resistance state which allows a high current to flow through the varistor 2a and enables the function of external overcurrent protection.

According to embodiment I, the electronic assembly of the assembly (2) has a circuit breaker (GDT) consisting of one or several gas blast circuit breakers.

According to embodiment II, the electronic assembly of the component 2 has a choke L integrated in the circuit, as shown in fig. 5, the component 2 having a performance that increases the protection level of the overall overvoltage protection device.

The solution of the invention reduces the possibility of arcing by the movable rotary disc 4 and the electronic assembly of the assembly 2 in which the branch with the GDT puffer breaker is operative in case of a rapid transition and the branch via the varistor 2d is operative in case of an occasional voltage increase. When the second connection electrode 2f has been disconnected, the rotating disk is transferred at a high angular velocity from one end position to the other end position under the spring force of the coil spring and covers the opening in the holder of the rotating disk, thereby preventing the generation of an arc.

Claims (4)

1. An overvoltage circuit breaker with a rotating disk and an electronic assembly to improve the operational reliability, characterized in that the electronic assembly of the assembly (2) comprises a resistor (PTC) with positive thermal coefficient, which is connected in parallel with a gas circuit breaker (GDT); the resistor (PTC) is in fact a resistor (2d), the puffer breaker (GDT) comprising puffer breakers (2b and 2 c); the common transfer point of the resistor (2d) and the gas circuit breaker (GDT) passes through a thermal component (V), which is simultaneously a connecting electrode (2f) arranged on the body of the varistor (2 a); the electronic assembly of the assembly (2) functions in such a way that: in case of a rapid transition, the branch with the gas blast circuit breaker (GDT) is operable, and in case of a sporadic voltage increase, the branch passing through the resistor (2d) is operable; the resistor (2d) having a positive thermal coefficient limits the current through the varistor (2a) when the applied voltage on each connection terminal exceeds the voltage threshold of the varistor (2 a); the varistor (2a) is switched to a low-resistance state which allows a high current to flow through the varistor (2a) and thus enables an external overcurrent protection function; said transition of said connection electrode (2f) triggers the movement of the rotating disc (4).

2. Overvoltage circuit breaker according to claim 1, characterized in that the electronic assembly of the component (2) comprises one or several gas blast circuit breakers (GDT).

3. Overvoltage circuit breaker as claimed in claim 1, characterized in that the electronic assembly of the component (2) has a choke (L) integrated in the circuit.

4. Overvoltage circuit breaker according to any of claims 1 to 3, characterized in that the assembly (2) with the varistor (2a), the puffer breakers (2b and 2c) and the resistor (2d) is arranged in a housing (1), wherein the resistor (2d) has positive thermal properties; the varistor (2a) has a first and a second connection electrode (2e and 2 f); a frame (2g) is simultaneously the first connecting electrode (2e) and protrudes from the shell (1); the support (3) of the rotating disc (4) is arranged on the frame (2g) of the assembly (2); said bracket (3) having a shallow circular groove (3a), said shallow circular groove (3a) having a convex cylindrical appendage (3b), said convex cylindrical appendage (3b) having a slot (3c) in the middle; an elliptical opening (3d) is provided at the bottom of the shallow circular groove (3 a); the rotary disk (4) has a circular hole (4a) at the center and a lower circular ring (4b), the lower circular ring (4b) having a split (4b '), the split (4 b') surrounding the lower circular ring (4b) in the vicinity of a first cylindrical appendage (4 c); an opening (4d) is provided in the rotary disc (4) on the opposite side of the first cylindrical appendage (4c), said opening (4d) starting from a second cylindrical appendage (4 e); the lower ring (4b) has the same height as the spring (5), the spring (5) being designed in such a way that: it starts from the first straight portion (5a) and is bent with the first semicircle to form a capital letter D; said spring (5) being wound around said first straight portion (5a) in such a way that: a second part of the spring in the line of the first straight part (5a) is also partly straight and ends in a semi-circular part (5b), the semi-circular part (5b) forming together with a second straight part (5c) a mirror image of the capital letter J; the locking plate (6) is provided with an oblong opening (6a) and a circular opening (6 b); said latch plate (6) having a first protrusion (6c) opposite said oblong opening (6a), said first protrusion (6c) followed by a short straight portion followed by a second protrusion (6 d); the housing (1) is closed by a cover (7) by means of two plugs (7 a); the assembly (2) is arranged inside the housing (1); the support (3) of the rotating disc (4) is arranged on the frame (2g) of the assembly (2) in such a way that: the connection portion of the frame (2g) is simultaneously the first connection electrode (2e) of the varistor (2 a); through the oval opening (3d), the second connection electrode (2f) is arranged on the varistor (2a), the second connection electrode (2f) being designed in such a way that: having a curved portion (2 f') in contact with the varistor (2 a); -the second portion (2f ") of the second connection electrode (2f) is straight and is bent in a third portion (2 f'") in parallel with the first connection electrode (2 e); the size and shape of the oblong opening (3d) is such that the second connection electrode (2f) of the varistor (2a) can be easily inserted therethrough, the oblong opening (3d) being placed at an angular distance away from the starting position of the rotary disc (4) such that after rotation around the convex cylindrical attachment (3b), the rotary disc (4) covers the oblong opening (3d) when in its end position; the second connecting electrode (2f) passes through the oval opening (3d) to reach the piezoresistor (2a) by means of temperature-sensitive scaling powder and is fixed on the upper side of the piezoresistor (2 a); the second connection electrode (2f) is held at a position in which the rotary disc (4) is in its starting position and the spring (5) is in a biased state; the rotating disc (4) is rotatably arranged in the shallow circular groove (3a) and passes through the circular hole (4a) to reach the convex cylindrical attachment (3b) of the bracket (3); said spring (5) being arranged at the centre of said shallow circular groove (3a) delimited by a lower circular ring (4b), said first straight portion (5a) of said spring (5) being engaged in said slot (3c) on said male cylindrical appendage (3 b); -a second portion of the spring (5) with the semi-circular portion (5b) is arranged around the second cylindrical attachment (4e) after the second connection electrode (2f) is arranged through the oblong opening (3d) and the opening (4d) in the rotary disc (4); said circular opening (6b) of said blocking plate (6) is inserted into the cylindrical appendage (3e) of said support (3) and, at the same time, into said oblong opening (6a) and into said second cylindrical appendage (4e) of said rotating disc (4); said second protrusion (6d) of the insertion seat (8a) is an indicator (8) of the initial status signaling.