DE202019005383U1 - Varistor with monitoring device - Google Patents

Abstract

Varistor (1) with monitoring device (Ü), having
A varistor ceramic (VAR), the varistor ceramic (VAR) being provided on a first side with a first connection (A1), the varistor ceramic (VAR) being provided on a second side, which is opposite the first side, with a second connection ( A2) is provided
A monitoring device (Ü) which is arranged on or adjacent to the first connection (A1) at a defined distance (d) different from 0 to the varistor ceramic (VAR),
The monitoring device (T) acquires information about the state of aging and makes it available via an interface (I / O),
• The monitoring device (Ü) being embedded on or at least in sections in an insulating sheath (ISO) of the varistor (1).

Description

The invention relates to a varistor with a monitoring device.

Background of the Invention

Overloads of electrical systems can essentially be divided into two categories. On the one hand, overloads occur in the form of a (permanently) excessive operating voltage. On the other hand, so-called transient overvoltages and / or surge currents occur, which can lead to an overload.

Overvoltage protection elements are used in a wide variety of voltage systems. The circuits used differ depending on the system.

For example, for so-called type 1 arresters (e.g. according to DIN VDE 0100-443 (VDE 0100-443): 2007-06 or IEC 60364-4-44: 2001-08 or DIN VDE 0110 / IEC publication 664), spark gaps are often based arrester used.

It is known that surge protection elements degrade when the protection task is accomplished.

For example, such overloads in a metal oxide varistor as an example of an overvoltage protection element can lead to a gradual degradation. This results in the occurrence of leakage currents and / or an increase in the leakage current.

Leakage currents convert heat in the overvoltage protection element. This heat can lead to further damage to the overvoltage protection element as well as to damage to neighboring systems due to heat input. The heat input can lead to further degradation, fire or an explosion.

In order to avoid this, surge protection elements are usually equipped with a thermal fuse to separate (less often to short circuit) the damaged surge protection element.

However, the situation then arises that damage is prevented by the separated overvoltage protection element, but the system that is actually to be protected is unprotected against overvoltages.

Similar situations arise for other surge protection elements, e.g. Spark gaps, gas discharge tube (GDT).

Surge protection elements are often arranged in a control cabinet. However, the surge protection elements are not always easily accessible there. Therefore, elements with remote reporting have been developed in the past.

However, this remote message was essentially designed to detect a triggering of a disconnection device. I.e. the user was given the opportunity to recognize a defective surge protection element.

Although this allows a targeted exchange, the system to be protected remains unprotected against overvoltages until it is replaced.

It would therefore be desirable to receive information about an impending failure at an early stage so that the surge protection element in question can be replaced in good time before the failure, in order to reduce the unprotected period to the duration of the replacement.

Based on this situation, it is an object of the invention to provide a varistor with a monitoring device which makes it possible to obtain knowledge of an aging state of the overvoltage protection element at an early stage.

The object is achieved by a varistor with monitoring device according to claim 1. Further advantageous refinements are in particular the subject of the dependent claims, the description and the figures.

• 1 eine schematische seitliche Darstellung von Elementen eines erfindungsgemäßen Varistors,
• 2 eine schematische Schnittdarstellung von Elementen eines erfindungsgemäßen Varistors in Ausführungsformen der Erfindung gemäß 1,
• 3 eine schematische Darstellung von Elementen und Aspekten von elektrischen Elementen gemäß Ausführungsformen der Erfindung,
• 4 eine schematische seitliche Darstellung von Elementen eines erfindungsgemäßen Varistors gemäß einer weiteren Ausführungsform der Erfindung, und
• 5 eine schematische Schnittdarstellung von Elementen eines erfindungsgemäßen Varistors in Ausführungsformen der Erfindung gemäß 4.

The invention is explained in more detail below with reference to the figures. In these shows:

• 1 2 shows a schematic lateral representation of elements of a varistor according to the invention,
• 2nd is a schematic sectional view of elements of a varistor according to the invention in embodiments of the invention 1 ,
• 3rd 1 shows a schematic illustration of elements and aspects of electrical elements according to embodiments of the invention,
• 4th is a schematic side view of elements of a varistor according to the invention according to another embodiment of the invention, and
• 5 is a schematic sectional view of elements of a varistor according to the invention in embodiments of the invention 4th .

The invention will be illustrated in more detail below with reference to the figures. It should be noted that different aspects are described, which can be used individually or in combination. I.e. Any aspect can be used with different embodiments of the invention, unless explicitly shown as a pure alternative.

Furthermore, for the sake of simplicity, only one entity is generally referred to below. Unless explicitly noted, the invention can also have several of the entities concerned. In this respect, the use of the words "a", "a" and "one" is only to be understood as an indication that in a simple embodiment at least one entity is used.

Insofar as methods are described below, the individual steps of a method can be arranged and / or combined in any order, unless the context does not explicitly state otherwise. Unless expressly stated otherwise, the processes can also be combined with one another.

Data with numerical values are generally not to be understood as exact values, but also include a tolerance of +/- 1% up to +/- 10%.

References to standards or specifications or norms are to be understood as references to standards or specifications or norms that apply / apply at the time of registration and / or - if priority is claimed - at the time of priority registration. However, this is not to be understood as a general exclusion of the applicability to subsequent or replacing standards or specifications or norms.

In 1 and 4th are schematic side representations of elements of a varistor according to the invention 1 shown.

The varistor 1 has a monitoring device Ü on. Furthermore, the varistor has at least one varistor ceramic VAR on. Even if in the following only reference to a varistor ceramic VAR will be taken, the invention can also be used in the same way with layered varistors. The varistor ceramic VAR is assumed to be rather flat in the following, ie the thickness is less than the side length of a surface. In this respect, a first side and a second side (corresponding to the area) are formed.

The varistor ceramic VAR is on a first page with a first connector A1 Mistake. The varistor ceramic is on a second side, opposite the first side VAR with a second connector A2 Mistake.

The monitoring device Ü is on or adjacent to the first connection A1 at a defined distance other than 0 d for varistor ceramics VAR arranged.

In the 4th and 5 is believed to be the monitor Ü eg on the connection A1 is arranged. In the 1 and 2nd it is assumed that the monitoring device is not arranged on a connection.

The monitoring device Ü captures information about the state of aging and provides information via an interface I / O.

Ie the monitoring device Ü is part of the varistor 1 and can, for example, in an insulating casing ISO , for example a housing or an encapsulation, arranged, in particular embedded.

Ie now the monitoring device Ü close to the object to be monitored (varistor ceramic VAR ) arranged. This enables real-time measurement and, for example, good recording of temperature profiles. By measuring temperatures and temperature profiles, the remaining service life and / or the remaining discharge capacity can be determined well on the basis of empirical data. This enables the user to recognize an impending failure at an early stage and to protect an endangered system from standstill and / or destruction by replacing the endangered varistor. This increases plant availability.

In one embodiment of the invention, the monitoring device has Ü via at least one superficial electrical interface on that of the varistor ceramic VAR opposite side. In the 2nd and 5 this is indicated by two hemispherical outward connections of the (wired) electrical interface. In addition to communication of information (in the sense of a communication interface I / O ) also a power supply for the monitoring device Ü provide. The location of the communication interface / superficial electrical interface is not relevant for the functioning of the invention. Rather, they can also be used in the area of the connections A1 , A2 or be located in any other suitable location. It should be noted that wireless interfaces also offer the possibility of energy supply.

In one embodiment of the invention, the monitoring device detects Ü Information about the state of aging at predefined time intervals. The predefined time intervals can be periodic or event-driven.

In a further embodiment of the invention, the interface I / O makes available information about the state of aging available at predefined time intervals. The information can be raw data and / or processed information. In particular, the information can include temperature (history) data.

According to a further embodiment of the invention, the monitoring device is Ü on a support P arranged. The carrier can be flexible or rigid. For example, the carrier P a circuit board made of a suitable material such as FR6 or polyimide. Flexible straps P can easily follow the contours of the varistor ceramic VAR and / or a connection A1 add, so that a good and fast heat transfer is possible where desired.

In one embodiment of the invention, the monitoring device Ü arranged on a leadframe. Lead frames can be produced inexpensively from stamped sheets and are just as suitable as carriers P for embedding in an insulating covering.

In a further embodiment of the invention, the interface I / O has a wireless interface. In particular, the wireless interface I / O can be a W-Lan, Bluetooth, RFID, ZigBeee, LTE, InterneteofThings, ... communication interface.

According to another embodiment of the invention, the interface I / O alternatively or additionally has a wired interface. In particular, the wired interface I / O can be a fieldbus, Interbus, LAN, ... communication interface. This can be done as in 2nd and 5 indicated the communication interface can be designed as a sliding contact, for example. Although only 2 connection elements are shown in the figures, the invention is not limited to a 2-wire interface.

In embodiments of the invention, the monitoring device Ü at least one sensor S1, S2 from the group comprising temperature sensor, magnetic field sensor. The temperature sensor can have, for example, a PT100 or similar, a PTC thermistor, a thermistor, an infrared sensor ... The temperature sensor is preferably in close proximity to the varistor ceramic VAR or a thermally connected element such as the connection A1 arranged so as to enable the fastest possible detection of heating. The magnetic field sensor and / or a current sensor can be realized by means of coils, in particular planar coils.

In yet another embodiment of the invention, the monitoring device has Ü continue to an evaluation device uC. The evaluation device uC can have, for example, a microcontroller, ASIC or FPGA, which queries and evaluates data from one or more sensors of the monitoring device continuously, periodically or on request. Obviously, neither the evaluation device uC nor the communication interface I / O have to be arranged in the immediate vicinity of the varistor ceramic. Likewise, a current sensor / magnetic field sensor can be located at a suitable point in relation to a connection A1 be arranged. A good thermal connection is only advantageous for a temperature sensor. This results in many degrees of freedom for the spatial arrangement of the other elements of the monitoring device, so that requirements for housing thicknesses, etc. can also be met.

Insofar as the term connection is used above in relation to the invention, any form of electrical connection, i.e. e.g. soldered, welded, by means of (pressed) needle electrodes, etc.

Reference list

1

Varistor

Ü

Monitoring device

VAR

Varistor ceramic

A1, A2

connection

d

distance

I / O

interface

P

carrier

S1, S2

sensor

uC

Evaluation device

ISO

insulating covering

Claims (10)

Varistor (1) with monitoring device (Ü), having A varistor ceramic (VAR), the varistor ceramic (VAR) being provided on a first side with a first connection (A1), the varistor ceramic (VAR) being provided on a second side, which is opposite the first side, with a second connection ( A2) is provided, • A monitoring device (Ü), which is arranged on or adjacent to the first connection (A1) at a defined, different from 0 (d) to the varistor ceramic (VAR), • The monitoring device (Ü) providing information about the state of aging is recorded and made available via an interface (I / O), • the monitoring device (Ü) being embedded on or at least partially in an insulating sheath (ISO) of the varistor (1). Varistor (1) after Claim 1 , characterized in that the monitoring device (Ü) has at least one superficial electrical interface on the side facing away from the varistor ceramic (VAR). Varistor (1) after Claim 1 or 2nd , characterized in that the monitoring device (Ü) acquires information about the aging state at predefined time intervals. Varistor (1) according to one of the preceding claims, characterized in that the interface (I / O) provides recorded information about the aging state at predefined time intervals. Varistor (1) according to one of the preceding claims, characterized in that the monitoring device (Ü) is arranged on a carrier (P). Varistor (1) according to one of the preceding Claims 1 to 4th , characterized in that the monitoring device (Ü) is arranged on a lead frame. Varistor (1) according to one of the preceding claims, characterized in that the interface (1/0) has a wireless interface. Varistor (1) according to one of the preceding Claims 1 to 6 , characterized in that the interface (I / O) has a wired interface Varistor (1) according to one of the preceding claims, characterized in that the monitoring device (Ü) has at least one sensor (S1, S2) from the group comprising a temperature sensor and a magnetic field sensor. Varistor (1) according to one of the preceding claims, characterized in that the monitoring device (Ü) furthermore has an evaluation device (uC).

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