DE102006052039A1 - Control cabinet with temperature monitoring - Google Patents

Abstract

The invention relates to a switchgear with a conductor arrangement with a plurality of conductors; with one or more modules (7) electrically connected to the conductor arrangement and / or one or more module interfaces (10) electrically connected to the conductor arrangement for connecting modules (7); with at least one temperature sensor (13) assigned to each module (7) and / or a temperature sensor (13) associated with each module interface (10) and / or a temperature sensor connectable via each module interface (10) for monitoring a temperature at the corresponding module (7) and a temperature interface connectable to the temperature sensors (13) for providing temperature information detected by the temperature sensors (13) on the modules (7) and via the module interfaces (10), respectively.

Description

The The invention relates to a control cabinet for receiving modules with a temperature control. The invention further relates to a temperature monitoring system for control cabinets.

Temperature increases Components in electrical equipment, such. Switchgear, are often Cause for losses and disorders and can hence the reliability reduce the investments.

at Electrical circuits become part of the transmitted or recorded electrical power in thermal output transformed. This is especially true for circuits in which high operating currents directed, processed and / or switched. There are temperature increases, which generally represent losses in energy transport be generated in ladders.

Farther can especially in control cabinets high temperatures on electrical contacts, e.g. on protective contacts, Sliding contacts and the like. Occur because often there is the least effective Conductor cross-section results when the contact is not on the the whole area is conductive or due to environmental influences or contact corrosion corroded. So occurs in particular in switchgear in which removable modules over releasable Module interfaces in control cabinets can be used or removed are the risk of localized strong heating at the contacting interface between control cabinet and module due to a possible increased Contact resistance on.

Therefore It is expedient, elevated temperatures in switchgear early to recognize.

Arrangements for monitoring the temperature of busbars, such as busbars in a switchgear are from the publications DE 692 12 594 T2 and US 5,319,356 known. There, the temperature is placed directly on the common bus bar of a conductor arrangement in the control cabinet with the aid of temperature sensors in order to detect the temperature. However, locally occurring temperature increases or deviations can not be detected. The temperature sensor arranged on the busbar may also be relatively far away from the location of the temperature increase, so that a temperature increase by the temperature sensor can not be detected at all or may be recognized too late.

It The object of the present invention is to provide a switchgear in which the occurrence of an undesirable temperature deviation fast and reliable can be detected and which is structurally simple.

These The object is achieved by the switchgear according to claim 1 and the temperature monitoring systems the claims 14 to 17 solved.

Further advantageous embodiments of the invention are specified in the dependent claims.

According to one first aspect, a switchgear is provided, which is a ladder arrangement with multiple conductors and one or more with the conductor assembly electrically connected modules and / or one or more with the Conductor assembly electrically connected module interfaces for connecting Includes modules. Furthermore, at least one associated with each module Temperature sensor and / or assigned to each module interface Temperature sensor and / or an over Each module interface connectable temperature sensor for monitoring a temperature provided on the corresponding module. aid a temperature interface with the temperature sensors or one or more suitable provided in the module o of the system Evaluation units is connected or connectable, is one of the temperature sensors at the modules or over the module interfaces provide detected temperature information. The detected temperature information may be an electrical quantity or be an evaluation signal that depends is generated by the detected temperature.

The Switchgear has the advantage of keeping the temperature at each of them located modules, i. at different locations within the switchgear, especially at positions where heating with increased likelihood occurs, monitors can be and a corresponding temperature information to further Evaluation provided at a temperature interface of the switchgear so that this e.g. detected and evaluated by a central processing unit can be.

The Modules are either fixed in the switchgear or after Need to be used in the switchgear and / or from the switchgear removable trained.

Farther can the respective temperature sensor on the corresponding module be arranged and electrically over a module interface with one or more conductors of the conductor arrangement be connected. In this way, a temperature information can be from the temperature sensors to those used in the switchgear Modules over detect the conductors of the conductor arrangement.

alternative or additionally can the respective temperature sensor at the module interface between the conductor assembly and the module to be arranged as temperature information the temperature at the module associated module interface to detect. This allows especially temperature increases due to increased Kontaktierungswiderständen be detected, especially if it is the module interface a detachable one Contacting device acts.

Preferably the module interface comprises a switchgear contact element and a module contact element which can be electrically coupled therewith when the module is inserted, wherein the associated temperature sensor even when removing the Module on the switchgear contact element or between the switchgear contact element and the module contact element remains. In this way can be avoided be to provide a temperature sensor on the module when the reliability the contacts of the modules should be ensured.

Of the Temperature sensor is preferably with the directly with the conductor assembly coupled switchgear contact element, so that at Take out the module of the temperature sensor in the switchgear remains. In this way, such temperature monitoring be provided without changes to have to provide on the modules.

Of the Temperature sensor can be glued to the switchgear contact element, with the help of a shrink tubing or a similar fastening device at the switchgear contact element be attached or suitably with a between switchgear contact element and module contact element be provided intermediate element provided.

Especially the temperature sensor can be attached to a cable plug shoe or a ring cable lug be attached, wherein the cable plug shoe or the ring cable lug with the switchgear contact element firmly connected, e.g. screwed, is or between the switchgear contact element and the module contact element be provided intermediate element, so that one at the respective module interface caused by a current flow extraordinary temperature increase can be detected by the corresponding temperature sensor.

According to one another embodiment Several modules are provided to which the corresponding temperature sensors are arranged, with the corresponding temperature sensors as Resistance temperature sensors, in particular designed as PTC sensors are and over the conductor of the conductor arrangement connects the temperature sensors in series are and are connected to the temperature interface as Temperature information a resistance value of the series-connected To provide temperature sensors. In this way it is possible the crossing one through the respective PTC sensor predetermined transition temperature by detecting the resistance value over the Temperature interface to detect.

In this regard is according to one Another aspect is a temperature monitoring system with a central processing unit and with one or more such Switchgear provided, the switchgear several modules have, on which the corresponding temperature sensors arranged are, with the corresponding temperature sensors as PTC sensors are formed, with over the conductor of the conductor arrangement connects the temperature sensors in series are and are connected to the temperature interface as Temperature information a resistance value of the series-connected To provide temperature sensors. The central unit is designed about the resistance value over determine the temperature interface and the determined To compare resistance value with a threshold, where a Temperature alarm is triggered, when the resistance value indicates a temperature exceeded.

According to one another embodiment the switchgear can Two temperature sensors on two assigned modules with different transition temperatures be provided. This makes it possible to define different critical temperatures for different modules when crossing a temperature limit over the temperature interface can be detected. When providing the Temperature sensors above In addition, with different jump resistances can be a distinction be made on which of the modules the temperature increase occurred is.

Based on such a switchgear can according to another aspect of a Temperature Monitoring System be provided, in which the central unit is designed to the resistance value over determine the temperature interface and the determined Resistance value with a first threshold and with a second higher threshold to compare, where a temperature alarm is triggered when the resistance value exceeds the first threshold but not the second threshold, being on the basis of an exceeding the second threshold, a temperature exceeded at a certain Module is detectable. The central unit can be either outside the system, in the system or on a module in the system be.

Farther An evaluation unit can be provided in the switchgear outside the module be and be connected to the temperature sensors to a temperature deviation to detect and over an output element associated with the corresponding module, either on the module or in the rest Plant is arranged to issue a temperature warning.

alternative can be provided on each module an evaluation, which with the corresponding temperature sensor is connected to a temperature deviation to detect and order over the corresponding module associated output element, either on the module or in the rest Plant is arranged to issue a temperature warning. To this Way, if e.g. above the central office over the temperature interface is a temperature deviation, e.g. either in the form of a temperature signal or in the form of an already preprocessed Evaluation signal that a certain occurred temperature deviation signaled, has recognized a service technician on site at the switchgear over the Output of the output element immediately recognize on which of the modules the temperature increase occurred, so that the search for the cause of the temperature increase simplified can be.

According to one Another aspect is a temperature monitoring system in one Central unit provided with one or more switchgear.

According to one Another aspect is a temperature monitoring system with a Central unit and provided with a first and a second switchgear, wherein in the first switchgear first PTC sensors with a first Transition temperature and a first jump resistance and in the second Switchgear second PTC sensors with a second from the first different transition temperature and with a second, from the first different jump resistance are each connected in series and connected to the corresponding temperature interface. The first and second switchgear continue to work with each other interconnects the first and second PTC sensors to each other are connected in series. The central unit is designed to a total resistance value information about the temperature interfaces to be determined, arising from the series connection of the first and the second PTC resistors results, and the determined total resistance information with a first threshold and to compare with a second threshold. Through the central unit is a temperature alarm for the first Switchgear triggers, if the total resistance information is the first threshold but does not exceed the second threshold and a temperature alarm for the second switchgear triggered, when the total resistance information exceeds the second threshold.

preferred embodiments The invention will be described below with reference to the accompanying drawings explained in more detail.

1 shows a temperature monitoring system with a switchgear according to a first embodiment of the invention.

2 shows a temperature monitoring system according to another embodiment;

3 shows a temperature monitoring system according to another embodiment;

4 shows a characteristic of a PTC sensor;

5A and 5B show variants of attaching the temperature sensor to the module interface between the module and the conductor arrangement;

6 shows attaching the temperature sensor to a cable plug shoe;

7 shows a temperature monitoring system with two switchgear according to another embodiment;

8th shows a temperature monitoring system according to another embodiment;

9 shows possible arrangements of temperature sensors in a multi-module module; and

10 shows a temperature monitoring system according to another embodiment ..

In 1 is a temperature monitoring system 1 with a switchgear 2 and with a central unit 3 shown. For communication with the central unit 2 indicates the switchgear 2 an interface 4 on that with the central unit 3 via a data bus that uses a suitable protocol, or via simple signal lines 5 which may be used for non-protocol bound signal transmission.

The switchgear 2 has a housing 17 and a number of modules 7 on. The switchgear 2 supplied in the embodiment shown, the modules 7 with electrical power. The modules 7 can include any electrical and electronic functions and therefore can perform both switching functions for currents and signals, power distribution functions, signal processing functions, and the like.

In the case 17 is a ladder arrangement 6 provided in the conductor rails 8th to supply the modules 7 with one or more supply voltages or for carrying switched currents (if one of the modules 7 a switching function perceives) are provided. The conductor rails 8th can carry high currents and, in the event that they carry a supply voltage, can be single or all in the switchgear 2 located modules 7 be electrically connected to a power supply for the corresponding modules 7 provide. Furthermore, the conductor arrangement 6 Signal lines and / or test leads 14 contain.

The modules 7 can be electrically connected to the conductors in the conductor arrangement 6 , the conductor rails 8th and the signal lines 14 , either hardwired or via module interfaces 10 , ie, for example, a detachable contacting device, detachable with the switchgear 2 be connected. The module interface 10 can in addition to supply conductor connections 11 to carry the power supply and to carry the switched currents also signal conductor connections 12 exhibit. About the signal conductor connections 12 can be a communication of the modules 7 over one in the ladder arrangement 6 located data bus or data signal lines and the like.

Furthermore, via the signal conductor connections 12 Direct measurements of electrical quantities, such as resistors, from on the module 7 located electrical components are made. The data bus or data signal lines in the conductor arrangement 6 are over the interface 4 with the central unit 3 connected.

In the embodiment of the 1 is in the modules 7 one temperature sensor each 13 provided a temperature at the corresponding module 7 , Preferably, at a position at which heat is expected to be detected, and a corresponding temperature information, for example in the form of an electrical variable, such as an ohmic resistance, across the module interface 10 , via the signal and measurement lines 14 the conductor arrangement 6 , over the interface 4 the central office 3 provides. In this way it is possible from a switchgear 2 to obtain a detailed temperature information indicating whether a temperature increase on one of the modules therein 7 has occurred and, depending on the width and design of the data bus or the data signal lines provided in the conductor arrangement, also information on which of the modules 7 the temperature deviation has occurred. Of course it is possible to have more than one temperature sensor 13 on the module 7 to be provided, each via the module interface 10 individually or in a suitable interconnection, eg as an electrical variable, are readable.

In 2 a temperature monitoring system according to another embodiment is shown. For these and below-described embodiments, elements having the same reference numerals correspond to elements of the same or comparable function.

The embodiment of the 2 differs from the embodiment of the 1 in that in the modules 7 provided temperature sensors 13 as PTC sensors 13 are formed. The PTC sensors 13 are via the corresponding module interface 10 with dedicated signal conductors in the conductor arrangement 6 connected, which ensure that the PTC sensors of the modules 7 be connected in series with each other and the arrangement of the temperature sensors connected in series 11 the modules 7 via the one designated temperature interface 19 that in the interface 4 is provided with the central unit 3 is connectable. The central unit 3 can now be a resistance information on the total resistance of the series-connected temperature sensors 11 over the temperature interface 19 to capture.

To connect in series with the insertable or removable modules 7 can ensure the module interfaces 10 in particular the contacting elements connected to the temperature sensor 11 in the module 7 are short-circuited with the module removed, with insertion of the module 7 this short circuit is reopened and instead via the two contacting elements of the PTC sensor 13 be created.

The PTC sensor is a resistance temperature sensor in the form of a so-called PTC thermistor whose characteristic curve is exemplified in FIG 4 is shown. A PTC sensor generally has a transition temperature at which the ohmic resistance of the PTC sensor increases by orders of magnitude. The magnitude of the increase of the ohmic resistance is called herein a jump resistance. In the arrangement of the PTC sensors connected in series, exceeding a temperature threshold value on one of the PTC sensors can therefore be detected by the total resistance of the series-connected PTC sensors correspondingly increasing. For several temperature sensors 13 on a module 7 These can be provided with different transition temperatures, so as to take into account the different heating of individual modules on the module and their temperature tolerance.

In 3 another embodiment of the present invention is shown. The embodiment of the 3 differs from the embodiment of the 2 in that the temperature sensor is not attached to the module 7 but at the module interface 10 is arranged. The module interface 10 includes a switchgear contact element 15 and a module contact element 16 which are coupled together when the module is inserted. To avoid having a temperature sensor in the module 7 and corresponding connection lines between the module 7 and conductor arrangement 6 must be provided for the temperature sensor is the temperature sensor 13 at the switchgear contact element 15 arranged. In this way, temperature increases due to a deteriorating contact resistance at the module interface 10 be detected on each of the modules 7 that with a module interface 10 in the switchgear 2 are used. When fixed in the switchgear 2 installed modules 7 is a deterioration of contacts or the connecting lines between the conductor arrangement and the module 7 not expected, so the temperature sensor 13 there as usual on the module 7 itself can be provided.

Also in the embodiment of the 3 the temperature sensors for the various detachable module interfaces are connected in series, so that the corresponding central unit 3 can determine a possible temperature deviation via a measurement of the resistance value of the series connection. In particular, in the pluggable or removable modules, such an embodiment is advantageous because it has a fixed wiring of the temperature sensors 13 enable.

In 5A and 5B are possible connection types of the temperature sensor at the module interface 10 shown as a module 7 a contactor 30 is used or a contactor 30 on a module 7 is arranged next to other modules. For example, as in 5A shown is the temperature sensor 13 on a cable plug shoe 25 (or a ring cable lug), and with a heat shrink tubing 26 be surrounded.

When the connection between the conductor arrangement 6 and the corresponding module 7 via a terminal clamp 27 (eg a cage terminal) is made, the cable plug shoe (ring cable lug) 25 between that with the conductor assembly 6 connected wire and the terminal clamp 27 can be used so that there can be detected Kontaktierungsverschlechterung in the form of a temperature increase.

Alternatively, the temperature sensor 13 , as in 5B shown, also to the connecting line between the conductor arrangement 6 and the module interface 10 be attached so that in the module interface 10 resulting heat via heat conduction of the connecting line to the temperature sensor 13 to be led.

The insertion of the temperature sensor 13 in the cable plug shoe (ring cable lug) is in 6 shown schematically. For this, the temperature sensor is inserted into a clamping section of the cable plug shoe (ring cable lug) 25 introduced and jammed there, so that this as intimate connection with the cable plug shoe (ring cable lug) 25 receives, in which the heat transfer resistance is minimized. In order to minimize external influences, the clamping section of the cable plug shoe (ring cable lug) is 25 , in which the temperature sensor is located, with a shrink tube 26 surround. It is also possible that the sensor is encapsulated with the ring cable lug, for example using an epoxy resin.

In the embodiments described above, the temperature sensors in the respective modules may be provided as PTC sensors with different transition temperatures, depending on the temperature at which a critical limit for the respective module 7 is exceeded.

In 7 a temperature monitoring system according to another embodiment is shown. Here is the central unit 3 with a first and a second switchgear 21 . 22 connected, in each of which modules 7 are provided. The temperature sensors 13 are either on the modules 7 in the switchgear 21 . 22 and / or at their module interfaces 10 arranged in the ways previously described or in any other distributed manner.

The temperature sensors 13 Each switchgear is connected in series and via a temperature interface in the interface 4 the total resistance of the arrangement can be tapped off via two measuring lines. The central office 3 is with the two switchgear 21 . 22 connected so that the temperature sensors 13 the first and the second switchgear 21 . 22 are connected in series via the corresponding temperature interfaces, so that all temperature sensors 13 both switchgear 21 . 22 connected in series with each other. This is from the central unit 3 the total resistance of the arrangement detectable. If now the PTC sensors 13 in the first switchgear 21 with a first transition temperature and with a first jump resistance and the PTC sensors 13 the second switchgear 22 with a second of the first different transition temperature and with a second of the first different Jump resistance are provided, it can be detected by the occurrence of a change in resistance that a fault in one of the switchgear 21 . 22 occured. Furthermore, it can be determined by the extent of the change in resistance, in which the switchgear 21 . 22 the temperature change has occurred. For more than two substations, in the above manner with the central office 3 In general, the PCT sensors are designed with different resistance changes that occur at different transition temperatures.

For detection of the switchgear 21 . 22 , in which the temperature increase has occurred, the central office must query the electrical resistance of the overall arrangement continuously or at predetermined times or intervals and detect the resistance change in a change, for example by a difference of the measured resistance before and after the occurrence of resistance change.

In all embodiments may in the switchgear evaluation 19 be provided either on the modules 7 or outside the modules 7 in the switchgear 2 are provided and with a the respective module 7 assigned output element 18 , such as a light indicator, are coupled so that the temperature sensor 13 in addition to being read by the central unit 3 also from the evaluation unit 19 can be read and a temperature increase or exceeding a maximum temperature by means of the output element 18 can be issued. This will allow a service technician who is due to one in the central unit 3 detected temperature exceeded a relevant switchgear investigated immediately detects the location of the temperature exceeded on the basis of the output of the output element, ie on which module 7 the temperature exceeded occurred.

As in 8th shown by the dashed blocks, the evaluation can 19 . 19 ' either on the modules 7 or outside the modules 7 in the switchgear 2 be arranged. Also the output elements 18 . 18 ' can either be on the modules 7 or outside the modules 7 be arranged. In particular, if the temperature sensors 13 on the modules 7 are arranged, evaluation units 19 and output units 18 on the corresponding modules 7 and if the temperature sensor 13 at the module interface 10 is arranged, the evaluation unit 19 ' and the output units 18 ' outside the modules 7 be provided. Is the evaluation unit 19 on the appropriate module 7 provided, this may also include a triggering device (not shown), with which a circuit can be interrupted when the evaluation unit 19 an inadmissible increase in temperature at the (one of) the temperature sensor 13 has detected assigned position.

9 shows a module 7 with several modules 40 , The individual modules are connected to each other via lines. At the contacting positions of the modules 40 with the individual lines are appropriate temperature sensors 13 provided so that occurring temperature increases can be detected. The connection of the individual temperature sensors with the module interface 10 is not shown for reasons of clarity.

In 10 the arrangement of the overall system according to another embodiment is shown. There are several temperature sensors 13 and the evaluation unit 19 on the respective modules 7 firmly mounted. When removing the module 7 These are therefore also taken. The temperature sensors 13 (three per module are shown) are on the one hand to the modules 40 in the module 7 itself and at the module interface 10 , the interface 4 is there with the evaluation units 19 connected and transmitted only information about the switching or triggering of the corresponding evaluation 19 , where the central unit 3 depending on this information generates a suitable alarm signal.

1

Temperature Monitoring System

2

switchgear

3

CPU

4

interface

6

conductor arrangement

7

module

8th

Conductor rails

10

Module interface

11

Supply conductor connections

12

Signal conductor connections

13

temperature sensor

14

Test leads

15

Switchgear contact element

16

Module contact element

17

casing

18

output element

19

evaluation

25

Cable accessory shoe

26

shrinkable tubing

27

protective element

30

contactor

40

module

Claims (17)

Switchgear comprising: A conductor arrangement with several conductors; One or more modules electrically connected to the conductor arrangement ( 7 ) and / or one or more module interfaces electrically connected to the conductor arrangement ( 10 ) for connecting modules ( 7 ); - at least one each module ( 7 ) associated temperature sensor ( 13 ) and / or each module interface ( 10 ) associated temperature sensor ( 13 ) and / or one over each module interface ( 10 ) connectable temperature sensor for monitoring a temperature at the corresponding module ( 7 ); - a temperature interface with the temperature sensors ( 13 ) is connectable to one of the temperature sensors ( 13 ) on the modules ( 7 ) or via the module interfaces ( 10 ) provide detected temperature information. Plant according to claim 1, wherein the module interface is designed to be a module ( 7 ) as required in the switchgear ( 2 ) and / or from the switchgear ( 2 to take out). Plant according to claim 1 or 2, wherein the respective temperature sensor ( 13 ) on the corresponding module ( 7 ) and electrically via a fixed contacting device or via the module interface ( 10 ) with one or more ladders ( 8th . 14 ) of the conductor arrangement ( 6 ) connected is. Installation according to one of claims 1 to 3, wherein a plurality of temperature sensors ( 13 ) on the corresponding module ( 7 ) and electrically via a fixed contacting device or via the module interface ( 10 ) with one or more ladders ( 8th . 14 ) of the conductor arrangement ( 6 ) are connected. Installation according to one of claims 1 to 4, wherein the respective temperature sensor ( 13 ) at the module interface ( 10 ) is arranged in order to display as temperature information the temperature at the module interface ( 10 ) of the assigned module ( 7 ) to detect. Plant according to one of claims 1 to 5, wherein the module interface ( 10 ) a switchgear contact element and thus at the onset of the module ( 7 ) electrically coupled module contact element ( 16 ), wherein the associated temperature sensor ( 13 ) so at the switchgear contact element ( 15 ) is arranged that the corresponding module ( 7 ) with the module contact element ( 16 ) as required in the switchgear ( 2 ) and / or from the switchgear ( 2 ) is removable. Plant according to claim 6, wherein the temperature sensor ( 13 ) to the switchgear contact element ( 15 ) is glued, stuck or screwed. Plant according to claim 6, wherein the temperature sensor ( 13 ) on the switchgear contact element ( 15 ) is secured by means of a shrink tube. Plant according to one of claims 1 to 8, wherein the temperature sensor ( 13 ) is attached to a cable plug shoe, wherein the cable plug shoe with the switchgear contact element ( 15 ), so that one at the module interface ( 10 ) caused by a current flow temperature deviation by the corresponding temperature sensor ( 13 ) is detectable. Investment ( 2 ) according to one of claims 1 to 9, wherein a plurality of modules ( 7 ) are provided, at which the corresponding temperature sensors ( 13 ) are arranged, wherein the corresponding temperature sensors ( 13 ) are designed as resistance temperature sensors, in particular as PTC sensors, wherein the temperature sensors are connected via the conductors of the conductor arrangement ( 13 ) are connected in series and with the temperature interface ( 4 ) are connected in order to use, as temperature information, a resistance value of the series-connected temperature sensors ( 13 ). Plant according to claim 10, wherein at least two temperature sensors are mounted on two respective modules ( 7 ) are provided with different transition temperatures. Plant according to one of claims 1 to 11, wherein on each module ( 7 ) an evaluation unit ( 18 ) provided with the respective temperature sensor of the corresponding module ( 7 ) to detect a temperature deviation and via a corresponding module ( 7 ) associated with the output element either on the module ( 7 ) or in the system is arranged to issue a temperature warning. Plant according to claim 1 to 11, wherein an evaluation unit ( 19 ) in the switchgear outside the module ( 7 ) is provided and connected to the temperature sensors to detect a temperature deviation and via a the corresponding module ( 7 ) associated output unit ( 18 ), either on the module ( 7 ) or in the remainder of the annex ( 2 ) is arranged to issue a temperature warning. Temperature monitoring system with a central unit ( 3 ) and with one or more switchgear ( 2 . 21 . 22 ) according to one of the preceding claims. Temperature monitoring system with a central unit ( 3 ) and with one or more switchgear ( 2 . 21 . 22 ) according to one of the claims 1 to 13, wherein the central unit ( 3 ) is designed to measure the resistance value via the temperature interface ( 4 ) and to compare the determined resistance value with a threshold value, wherein a temperature alarm is triggered when the resistance value indicates a temperature exceeded. Temperature monitoring system with a central unit ( 3 ) and with one or more switchgear ( 21 . 22 ) according to one of claims 1 to 13, wherein the central unit ( 3 ) is configured to determine the resistance value across the temperature interface and to compare the detected resistance value with a first threshold and a second threshold, wherein a temperature alarm is triggered when the resistance exceeds the first threshold, wherein based on exceeding the second threshold a temperature overrun at a particular module ( 7 ) is detectable. Temperature monitoring system with a central unit ( 3 ) and with a first and a second switchgear ( 21 . 22 ) according to one of claims 1 to 13, wherein the PTC sensors ( 13 ) of the first switchgear ( 21 ) a first transition temperature and a first jump resistance and the PTC sensors ( 13 ) the second switchgear ( 22 ) have a second, different from the first transition temperature and a second, different from the first jump resistance, wherein the first and the second switchgear ( 21 . 22 ) are connected in such a way that the PTC sensors ( 13 ) of the first and the second switchgear ( 21 . 22 ) are connected in series with each other, wherein the central unit ( 3 ) is designed to provide total resistance value information via the temperature interfaces ( 4 ) and to compare the determined resistance value information with a first threshold value and with a second threshold value. 3 ) a temperature alarm for the first switchgear ( 21 ) is triggered when the total resistance value information exceeds the first threshold and a temperature alarm for the second switchgear ( 22 ) is triggered when the total resistance value information exceeds the second threshold.