Transformer, arc detection system and method for detecting an arc
Patent Information
- Application Number
- EP2023825068
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-12-08
- Filing Date
- 2023-12-08
- Publication Date
- 2025-10-15
AI Technical Summary
Existing arc detection systems in transformers face challenges due to high temperatures, magnetic and electric field strengths, and distance limitations, leading to reduced detection capability and accessibility issues, particularly with semiconductor-based light-sensitive sensors.
The use of a flexible optical waveguide to transmit electromagnetic radiation from arcs to a light detector positioned outside the transformer, allowing for arbitrary placement and reducing wear, with branching and sealed feedthroughs for enhanced coverage and accessibility, and the use of semiconductor-based sensors at normal ambient conditions.
This solution enables reliable and early detection of arcs, including low-intensity ones, with reduced maintenance and increased safety by positioning detectors in a protected environment, while allowing for easy adaptation to various transformer sizes and retrofitting.
Smart Images
Figure 1.1
Abstract
Description
[0001] Transformer, arc detection system and method for detecting an arc
[0002] The present invention relates to a transformer or a rectifier transformer or a phase shifter or choke coil with an arc detection system, as well as the arc detection system according to the generic term of claims 1 and 11 . The invention further relates to a method for arc detection.
[0003] Transformers, rectifier transformers, phase shifters and choke coil comprise a tank containing one or more coils, some of which are coupled to each other via their magnetic field. In the case of a rectifier transformer, semiconductor elements are also included. These are cooled by dielectric coolants, such as dielectric oils. During their service life of up to 50 years, the power transmitted through them, together with environmental influences such as extreme weather conditions, can cause wear on the insulation of the transformer windings. This wear can lead to short circuits, which cause arcing. These arcs can lead to a temperature rise and gas evolution accompanied by a pressure rise inside the transformer housing. The pressure can build up to such an extent that the housing ruptures and the coolants and gases it contains can cause a fire or even an explosion if they come into contact with air.
[0004] Therefore, in order to protect the transformer and its environment from damage, various safety systems for transformers have been developed. Electrical protection systems, for example a relay with differential current measurement, shut down the transformer when anomalies occur. In transformers with liquid-based cooling, Buchholz relays are further used to monitor the level of the coolant and the internal pressure of the transformer simultaneously. In the event of damage, the transformer is connected to a surge tank after a valve is opened, allowing the overpressure to dissipate by draining the coolant. In addition, an inert gas, such as nitrogen, can be introduced into the tank. The important thing here is that the anomaly is detected quickly.
[0005] For this purpose, transformer protection devices with semiconductor-based light-sensitive sensors have recently been developed. These sensors are placed inside a transformer housing to detect the electromagnetic radiation of the arcs. Thus, the speed of light can be exploited to initiate the safety measures quickly.
[0006] Such a transformer protection device is known, for example, from US 2008 / 0192389 A 1 or US 2017 / 0133836 A1.
[0007] However, the semiconductor-based light sensors are worn out by high temperatures, typically more than 130 °C, magnetic field strengths of more than 1000 A / m and electric field strengths of more than 1 kV / m generated by the current-carrying windings of the transformer. In addition, to monitor the occurrence of arcs in transformers with greater power throughput and with the appropriate size, multiple sensors are required because the detection capability of the light sensors decreases with distance from the arc. In addition, such sensors are difficult to access for installation or maintenance purposes. The effects of temperature, distance, oil, and electromagnetic fields on the semiconductor-based sensors have been described, for example, by Akbari et al. "Possibility of electric arc detection in power transformers by directly embedded photoconductive elements in the transformer tank ", Transformers Magazine Volume 9, Issue 1 , 2022.
[0008] Based thereon, it is the object of the present invention to provide a transformer with an arc detection system, or an arc detection system for such a transformer, which can withstand the conditions in the transformer housing, and at the same time is easily accessible and compatible with various transformer sizes. It is further an object of the invention to provide a correspondingly improved method for arc detection in a transformer.
[0009] According to the invention, this task is solved by the features of claim 1.
[0010] If the at least one light transmission means, in particular an optical waveguide, itself receives the electromagnetic radiation emitted by an arc occurring between the windings of a transformer and transmits it to the light detector, the position of the light detector can be chosen arbitrarily. This makes the positioning of the light detector independent of the position of the windings. Thus, one can choose a position outside the transformer. By using the detector in a less harsh environment, wear is reduced and at the same time the detector itself becomes easily accessible. The use of the fiber optic cable further makes it possible to adapt the device to different transformer sizes. For this purpose, it is sufficient to select a suitable length.
[0011] According to one embodiment of the transformer, the at least one light transmission means may be a flexible optical fiber. Preferably, the bending radius can be at least ten times larger than the fiber diameter, under mechanical tension at least fifteen times. For fiber diameters of 1 mm, the bending radius should thus be at least 15mm.
[0012] The use of electrical sensors in the transformer is limited to voltage-free parts, usually the boiler wall. Since fiber optic cables are typically not electrically conductive, they can also be laid directly on live parts in the transformer, even if these have a high voltage. A flexible fiber optic cable can be laid around the windings and easily adapted to the different sizes and variants of transformers, allowing the light transmission medium to be laid in a way that is particularly advantageous for retrofitting. This also makes it possible to detect small arcs and further increase the safety of the system. According to one embodiment of the transformer, the at least one light transmission means may be at least partially, in particular completely, free of a light shielding element in a first section within the housing. This enables the reception of electromagnetic radiation over a large area and not only at the end surface. By light-shielding element is usually meant a light-impermeable coating.
[0013] Thus, the sensitivity of detection can be improved over a large volume.
[0014] According to one embodiment of the transformer, the light transmission means may include at least one branch having a plurality of arms within the housing.
[0015] By branching, a large volume coverage can be achieved for the detection of electromagnetic radiation.
[0016] According to one embodiment of the transformer, the at least one light transmission means may comprise a second section outside the housing that is shielded from external electromagnetic radiation, in particular sunlight. This may be achieved by at least one opaque layer.
[0017] The light transmission medium is thus protected from the penetration of external electromagnetic radiation, such as sunlight. Detection is thus limited to the safety-relevant arcs inside the transformer housing. Further, the position of the light detector outside the transformer can be chosen arbitrarily. Thus, the reliability of the detection of safety-relevant signals and the accessibility of the light detector can be increased at the same time.
[0018] According to one embodiment of the transformer, the at least one light transmission means may be guided through the housing of the transformer by means of a sealed feedthrough.
[0019] By using a sealed feedthrough, the normal operation of the transformer is not restricted with improved safety monitoring. In addition, the sealed feedthrough also allows the possibility of coaxially connecting different light transmission means at the feedthrough. Thus, a light transmission means free of a light shielding element is used in the transformer and a second light transmission means with light shielding element on the outside is used.
[0020] Thus, mounting the arc detection system with a sealed feedthrough not only increases the safety of the transformer, but also makes it easier to retrofit the arc detection system to transformers already shipped that include appropriate connections, such as blind flanges.
[0021] According to one embodiment of the transformer, the at least one light transmission means may be arranged in proximity to one or more windings of the transformer. In particular, the at least one light transmission means may be arranged within one or more windings and / or may be wound together with one or more windings. So that the function of the transformer is not disturbed in this case, the material of the light transmission means is preferably electrically insulated.
[0022] Due to the proximity of the light transmission medium to the current-carrying windings of the transformer, even arcs with low intensity, in particular below 1 candela, can be detected. Arcs that do not cross the entire insulating distance, so-called partial discharges, can also be detected. This means that the system can be reacted to at an early stage. This leads to increased system reliability.
[0023] According to one embodiment, the transformer may comprise a control unit designed to shut down the transformer and / or open an inlet valve on the transformer housing and / or initiate the introduction of an inert gas via an inlet valve when the light detector detects electromagnetic radiation via the at least one light transmission means. In particular, the control unit disconnects the transformer from the power supply when the signals of the light detector exceed a corresponding limit value with respect to duration and / or intensity and / or wave spectrum.
[0024] Disconnecting the transformer from the power supply at an early stage prevents further energy input into the transformer. Opening the valve can relieve excess pressure. Introducing an inert gas reduces the risk of fire occurring. The safety of the transformer can be increased by this light detection system and the maintenance work following the described case of damage is comparatively low.
[0025] According to one embodiment of the transformer, the first section of the at least one light transmission means may be at least 0.5 meters long.
[0026] This allows large areas of a transformer to be monitored, especially if the entire section, including the lateral section, is free of a light-shielding element.
[0027] According to one embodiment of the transformer, the second section of the at least one light transmission means may be at least 0.5 meters long, preferably at least 5 meters long. Even lengths of more than 50 meters are possible.
[0028] The light detector can be positioned to be easily accessible without limiting operation due to the length of the second section of the light transmission means.
[0029] According to one embodiment of the transformer, the light detector may be one of the following: semiconductor-based photosensitive sensors, in particular a photodiode, an avalanche photodi- ode, a phototransistor, a photoresistor, a CCD sensor, an APS-CMOS sensor, a pyroelectric sensor, or a vacuum tube-based photosensitive sensor, in particular a photomultiplier or a photocathode.
[0030] Since the sensors can be located outside the transformer housing, such sensors can be used that can be used at normal ambient temperatures and pressures.
[0031] The task of the invention is also solved with an arc detection system according to claim 12.
[0032] When such an arc detection system is installed in a transformer, the at least one light transmission means, in particular an optical fiber, can receive the electromagnetic radiation when an arc occurs in the transformer. At the same time, the light detector can be located outside the tank. This can increase the reliability of the light detection and the safety of the transformer.
[0033] According to one embodiment of the arc detection system, the at least one light transmission means may be a flexible optical fiber. This should be designed in such a way that bending radii at least ten times larger than the fiber diameter, and at least fifteen times larger under mechanical stress, can be realized. For fiber diameters of 1 mm, bending radii of at least 15 mm should be possible. This enables the advantages already mentioned above of a flexible optical fiber in the transformer.
[0034] According to one embodiment, the portion of the light transmission means that is configured to be positionable within the housing may be at least partially, preferably completely, free of a light shielding element. This allows reception of electromagnetic radiation over a large area and not only at the end surface. By the term light-shielding element is usually meant an opaque coating. This allows the sensitivity of the detectors to be improved over a larger volume.
[0035] According to one embodiment of the arc detection system, the section of the light transmission means configured to be positioned within the housing may have at least one branch with multiple arms. This provides the advantages mentioned above and, in particular, increases flexibility in routing.
[0036] According to one embodiment of the arc detection system, the at least one light transmission means may comprise a second section configured to be positionable outside the housing and shielded from electromagnetic radiation, in particular from sunlight. This is achieved by at least one opaque layer. This increases the flexibility of the assembly without limiting the detection capability. According to one embodiment, the arc detection system may comprise a sealed feedthrough configured to allow the at least one light transmission means to pass through the housing of a transformer. This leads to the aforementioned advantages of a sealed feedthrough in the transformer. In particular, an optical waveguide can be passed through in a sealed manner, or two optical waveguides can be coaxially connected to each other at the seal itself.
[0037] According to one embodiment of the arc detection system, the first section of the at least one light transmission means may be at least 0.5 meters long. Thus, monitoring of large areas is also possible.
[0038] According to one embodiment of the arc detection system, the second section of the at least one light transmission means may be at least 0.5 meters long, preferably at least 5 meters long. The advantages of having a second section of the light transmission element at least 0.5 meters long when used in the transformer have been discussed above.
[0039] According to one embodiment of the arc detection system, the light detector may be one of the following: semiconductor-based photosensitive sensors, in particular a photodiode, an avalanche photodiode, a phototransistor, a photoresistor, a CCD sensor, an APS-CMOS sensor, a pyroelectric sensor, or a vacuum tube-based photosensitive sensor, in particular a photomultiplier or a photocathode.
[0040] These light detectors enable the advantages already described for use in a transformer.
[0041] The invention also relates to a power transmission device, in particular a rectifier transformer or a phase shifter or a choke coil with an arc detection system, according to any one of claims 12 to 20.
[0042] The task of the invention is also solved by a method according to claim 22.
[0043] With the method, arcs can be detected quickly and reliably, since the speed of light is used to detect arcs that occur, but at the same time the light detector can be positioned in a protected manner. By quickly initiating protective measures, the transformer, as well as its surroundings, can be protected from fire and explosions. At the same time, matching the signals with the limit values prevents unnecessary intervention and thus makes the process more economical. The invention is explained in more detail below with reference to the following figures. The invention is described in further detail below with reference to the figures, using examples of embodiments. Here, individual features of the respective embodiment examples can be combined with each other as desired in order to achieve new embodiments according to the invention.
[0044] Figure 1 schematically shows a transformer according to the invention with an arc detection system according to a first embodiment.
[0045] Figure 2 schematically shows a transformer with an arc detection system according to a second embodiment.
[0046] Figure 3 shows an arc detection system according to a third embodiment of the invention.
[0047] Figure 1 shows a transformer 1 with a housing 3 which can be closed with a cover 5. Schematically shown inside the housing 3 are a high-voltage winding 7 and a low-voltage winding 9, which are wound around a common iron core 11. Depending on the transformer, there may be more than one high-voltage winding and low-voltage winding. The high voltage winding 7 is connected to external first insulated contacts 15a and 15b via high voltage interconnection lines 13. The low- voltage winding 9 is correspondingly connected to external second insulated contacts 19a and 19b via low-voltage connection lines 17. The external high-voltage line 21 and the external low- voltage line 23 are connected to these.
[0048] The high and low voltage windings 7, 9 are cooled by a coolant 25 filled into the tank 3. Dielectric fluids, such as oils, are usually used for this purpose. These may be flammable.
[0049] Schematically shown are also known protection devices for the transformer 1 , such as a fire detector 27, a Buchholz valve 29, a drain valve 31 for coolant 25, an inlet valve 33 for blowing in an inert gas, for example nitrogen, a relay with differential current measurement 35, a circuit breaker 37 on the high voltage side and a circuit breaker 39 on the low voltage side. These devices are connected to a control unit 41 .
[0050] The transformer 1 may also be equipped with further protective devices, such as a bursting disc. Such a rupture disc breaks at a predetermined pressure so that coolant 25 can flow off to relieve the pressure before the housing 3 bursts open. The transformer 1 may also be equipped with fewer protective devices. The control unit 41 is designed to initiate safety measures such as shutting down and / or draining coolant 25 and / or blowing in an inert gas, such as nitrogen, when predetermined parameters are present, such as the Buchholz valve 31 hitting and / or an unusual voltage value at the relay 35. According to the invention, the transformer further comprises an arc detection system 43. The arc detection system 43 comprises a light transmission means 45 and a light detector 47. The arc detection system 43 may be arranged on the housing 3 of the transformer 1 . In this case, according to the invention, the light detector 47 is arranged outside the transformer 1 and the light transmission means 45 is arranged inside the same. The arc detection system 43 is also connected to the control unit 41 . According to a variant, more than one arc detection system 43 could be provided.
[0051] The light transmission means 45 may be an optical waveguide. Preferably, the optical waveguide is designed in such a way that it can receive light from outside at least partially, preferably over its entire length. Thus, a larger area inside the transformer 1 can be monitored than in comparison with the prior art. The optical fiber can be a jacketed or unsheathed fiber optic cable. In order to allow light to enter not only at the end of the fiber optic cable, the otherwise usual additional plastic sheathing is omitted or at least partially removed. Since the signals do not involve the transmission of information streams, it is irrelevant whether all or only part of the light that occurs is fed into the optical fiber. What matters is that at least a portion of the light is passed in the fiber optic cable so that it can strike the light detector 47 at the end. To detect an arc, it may be sufficient if less than 1% of the light enters and remains in the fiber.
[0052] The light detector 47 may be a semiconductor-based light detector, such as a CCD camera, a photodiode, an avalanche photodiode, a phototransistor, a photoresistor; an APS-CMOS camera, a pyroelectric sensor, or a vacuum tube-based photosensitive sensor, such as a photomultiplier or a photocathode.
[0053] In accordance with the invention, the arc detection system 43 in the transformer 1 functions as follows.
[0054] If an arc occurs between the high-voltage winding 7 and the low-voltage winding 9 or elsewhere, the light transmission means 45 can detect the electromagnetic radiation emitted by the arc. At least a portion of the radiation then passes through the light transmission means 45 to the light detector 47, where it can be detected. The corresponding signal is then transmitted from the light detector 47 to the control unit 41. If a predetermined limit value is exceeded with regard to intensity and / or duration and / or wave spectrum of the detected radiation, the control unit will initiate one or more of the safety measures described above.
[0055] Since the light detector 47 is mounted outside the housing 3 according to the invention, it is protected from the heat and electric field inside the transformer 1 , thus simultaneously increasing the accessibility, reliability and service life of the light detector 47 and thus improving the safety of the transformer 1.
[0056] Figure 2 shows a transformer 51 according to a second embodiment. Features with reference signs which have already been used in connection with transformer 1 of the first embodiment are not described again. Reference is made to the description of Figure 1.
[0057] Compared to the first embodiment, the arc detection system 53 used differs from the arc detection system 43 in that the light detector 47 is not arranged on the housing 3, but is solved further away from it, for example in the vicinity, or is arranged in the control unit 41 .
[0058] The illustrated arc detection system 53 in the second embodiment thereby comprises a light transmission means 55, which can be divided into a first section 55a inside the housing 3 and a second section 55b outside the housing 3.
[0059] The first section 55a of the light transmission means 55 in the second embodiment further comprises two arms 57a and 57b. Arm 57a is inserted or wrapped into the low voltage winding 9. Arm 57b extends to the high voltage winding 7 and, like arm 57a according to one variant, can also be introduced into the winding. According to further variants, the light transmission means 55 can have even more arms leading into other areas of the housing 3. Thanks to the use of several arms, it is sufficient to use one detector 47.
[0060] Since the wires of windings 7 and 9 are current-carrying, the probability of an arc occurring within transformer 1 in this area is high. Due to the close proximity of the light transmission means 55 to the windings 7 and 9, arcs with very low intensity, in particular below 1 candela, can also be detected. Arcs that do not cross the entire insulating distance, so-called partial discharges, can also be detected. In this way, any wear of the line insulation can be detected at an early stage, which increases the safety of the overall system.
[0061] In the second embodiment, the light transmission means 55 passes from the interior of the housing 3 to the exterior via a sealed feedthrough 59 and terminates at the light detector 47. Here, the light detector 47 is connected to the control unit 41 via a cable 63.
[0062] The light transmission means 55 may, as in the first embodiment, be an optical fiber, for example a jacketed or unjacketed optical fiber. In particular, as in the first embodiment, the light transmission means 55 may be a flexible optical fiber which can thus be adapted to the interior of the transformer 1 . This particularly facilitates retrofitting to transformers 1 with different sizes and shapes. In addition, the safety of the overall system can once again be increased, since virtually arbitrary routing of the fiber optic cable makes it possible to optimize arc detection by placing the fiber optic cable in the vicinity of the areas at risk.
[0063] In particular, light transmission means with a minimum length of 0.5 meters of the first section of the light transmission means 55a are used.
[0064] In the second embodiment, the light wave transmission means 55 is designed in such a way that light can also penetrate the transmission means 55 laterally over a large part of its length and not only at the end. According to one variant, however, one or more sections, in particular further away from the areas where light arcs are expected, within the housing 3 may also be covered with an opaque light-shielding element 61 .
[0065] The light transmission means 11 is provided externally with an opaque light shielding element 61 , in particular an opaque coating. The opaque light-shielding element 61 thereby prevents external light rays from the environment, for example sunlight, from entering the light transmission means 55. This ensures that the light detector 47 does not receive any false signals, thus preventing the system from being switched off unnecessarily.
[0066] According to one variant, two different light transmission means can be used inside and outside the housing 3, which are then coaxially connected to each other at the feedthrough 59.
[0067] The sealed feedthrough 59 increases the compatibility of the arc detection system with various transformer models, which has a particularly positive effect on its suitability for retrofitting. In addition, sealing can increase system safety.
[0068] Since the light absorbed into the optical waveguide no longer leaves it, and the absorption rate is low, in particular less than 20% per kilometer, the second section of the light transmission means 55b can be relatively long, for example even over 50 meters. Thus, the location of the light detector 47 can be chosen to be any distance from the transformer 1 , in particular within the control unit 41 . The light detector is thus arranged to be easily accessible and protected.
[0069] Figure 3 shows an arc detection system 71 according to a third embodiment separate from the transformer. Such an arc detection system 71 can be used as a retrofit set in order to install the fuse functionality according to the invention also subsequently in a transformer, for example at a blind flange. Features with reference signs already used in connection with transformer 1 or 51 of the first or second form of construction are not described again. Reference is made to the description of figures 1 and 2, respectively. The arc detection system 71 according to the third embodiment takes up the embodiment of the arc detection system 53 of the second embodiment. According to a variant, the arc detection system 43 of the first embodiment may be used.
[0070] The arc detection system 71 includes a light transmission means 55, a light detector 47, and a sealed feedthrough 59. The feedthrough 59 allows sealing with respect to a housing by means of O-rings on the flange surface. The light transmission means 55 may be disposed through the feedthrough 59, or two light transmission means may be coaxially connected on the other side of the feedthrough.
[0071] The light transmission means 55 may be divided into a first section 55a and a second section 55b.
[0072] The light transmission means 55 in the second section 55b is covered with a light shielding element 61 towards the feedthrough 59. Subsequently, the light transmission means branches into two arms 57a and 57b without light shielding element 61 in the first section 55a. Alternatively, the light transmission means may have more than two arms or only one arm in the first section 55a.
[0073] The light transmission means 55 in the second section 55b between the feedthrough 59 and the light detector 47 is completely covered by the light shielding element 61 to prevent light, such as sunlight, from entering.
[0074] The light detector 47 can be connected to an external control unit via a connector 73.
[0075] The arc detection system 71 can thus be used to retrofit existing transformers. For this purpose, the optical waveguide is inserted in the first area 55a through an opening on the transformer housing. Then the feedthrough is sealingly fastened to the flange of the transformer and the light detector 47 is connected to the control unit. At the same time, route arms 57a, 57b inside the detector housing and bring them close to the critical areas of the transformer.
[0076] Thanks to the invention, it is possible to take advantage of light detection to quickly detect problems in the transformer and initiate countermeasures, while at the same time it is possible to place the sensitive detectors outside the transformer and thus protect them from the harsh conditions inside the transformer. For this purpose, according to the invention, one uses a light transmission means that picks up light from arcs and transmits it to the detector. This is in contrast to the prior art, in which the light in the transformer is detected by the detector and only the signal is transmitted to the outside via optical fibers. The invention has been explained with reference to a transformer, but it is equally applicable to other power transmission devices, for example in a rectifier transformer or a phase shifter or choke coil.
[0077] References signs
[0078] I Transformer
[0079] 3 Housing (of the transformer)
[0080] 5 Housing cover
[0081] 7 High voltage winding
[0082] 9 Low voltage winding
[0083] I I Iron core
[0084] 13 High voltage interconnectors
[0085] 15a, 15b First isolated contacts
[0086] 17 Low voltage interconnectors
[0087] 19a, 19b Second isolated contacts
[0088] 21 High voltage line
[0089] 23 Low voltage line
[0090] 25 Coolant
[0091] 27 Fire alarm
[0092] 29 Buchholz valve
[0093] 31 Drain valve
[0094] 33 Inlet valve
[0095] 35 Relay
[0096] 37 Circuit breaker
[0097] 39 Circuit breaker
[0098] 41 Control unit
[0099] 43 Arc detection system
[0100] 45 Light transmission medium
[0101] 47 Light detector Transformer Arc detection system Light transmission medium a First section of the light transmission mediumb Second section of the light transmission mediuma First arm of the light transmission medium b Second arm of the light transmission means Implementation Light shielding element inside Cables Arc detection system Connection
Claims
Claims Transformer (1) having a housing (3) and at least one arc detection system (43) which has at least one light transmission means (45, 55), in particular an optical waveguide, and a light detector (47) for receiving the electromagnetic radiation transmitted via the light transmission means, characterized in that the light detector (47) is arranged outside the housing (3), and the light transmission means (45, 55) is arranged at least partially within the housing (3), and at least part of the light transmission means (45, 55) within the transformer (1) is adapted to receive electromagnetic radiation occurring within the housing (3). Transformer (1) according to claim 1 , characterized in that the at least one light transmission means (45, 55) is an optical waveguide, in particular a flexible optical waveguide. Transformer (1) according to claim 1 or 2, characterized in that the light transmission means (45, 55a) within the housing (3) is at least partially, in particular completely, free of a light shielding element (61). Transformer (1) according to any one of claims 1 to 3, characterized in that the light transmission means (45, 55a) comprises at least one branching with a plurality of arms (57a, 57b) within the housing (3). Transformer (1) according to any one of claims 1 to 4, characterized in that the at least one light transmission means (55) comprises a second portion (55b) outside the housing(3) which is shielded against external electromagnetic radiation, in particular sunlight. Transformer (1) according to any one of claims 1 to 5, characterized in that the at least one light transmission means (55) is guided through the housing (3) of the transformer (1) using a sealed feedthrough (59). Transformer (1) according to any one of claims 1 to 6, characterized in that the at least one light transmission means (55) is arranged in the vicinity of one or more windings of thetransformer (1), in particular is arranged within one or more windings and / or is wound together with one or more windings Transformer (1) according to any one of claims 1 to 7, comprising a control unit (41) configured to shut down the transformer and / or open a drain valve (31) on the transformer housing and / or initiate the introduction of an inert gas, in particular nitrogen, via an inlet valve (33) when the light detector (47) detects electromagnetic radiation via the at least one light transmission means (45, 55). Transformer (1) according to any one of claims 1 to 8, characterized in that the first portion of the at least one light transmission means (45, 55a) is at least 0.5 meter long. Transformer (1) according to any one of claims 1 to 9 in combination with claim 5, characterized in that the second portion of the at least one light transmission means (55b) is at least 0.5 meters, preferably at least 5 meters long. Transformer (1) according to any one of claims 1 to 10, characterized in that the light detector (13) is one of the following: semiconductor-based photosensitive sensors, in particular a photodiode, an avalanche photodiode, a phototransistor, a photoresistor, a CCD sensor, an APS-CMOS sensor, a pyroelectric sensor or a vacuum tube-based photosensitive sensor, in particular a photomultiplier or a photocathode. Arc detection system (43), in particular for use as an arc detection system in a transformer (1), according to any one of claims 1 to 11 , comprising at least one light transmission means (45, 55), in particular an optical waveguide, and a light detector (47) for receiving electromagnetic radiation transmitted via the light transmission means (45, 55), characterized in that the light detector (47) is designed such that it can be arranged outside the housing (3) of a transformer (1), and the light transmission means (45, 55) is designed in such a way that it can be arranged at least partially within the housing (3) of a transformer (1), andat least a part of the light transmission means (45, 55), which is adapted to be arranged within the housing (3) of the transformer (1), is adapted to receive the electromagnetic radiation occurring. The arc detection system (43) of claim 12, characterized in that the at least one light transmission means (45, 55) is a flexible optical fiber. Arc detection system (43) according to claim 12 or 13, characterized in that the portion of the light transmission means (45, 55a) adapted to be positionable within the housing (3) is at least partially free, preferably completely free, of a light shielding element (61). Arc detection system (43) according to any one of claims 12 to 14, characterized in that the portion of the light transmission means (55a) adapted to be positioned within the housing (3) comprises at least one branch having a plurality of arms (57a, 57b). Arc detection system (43) according to any one of claims 12 to 15, characterized in that the at least one light transmission means (55) comprises a second portion (55b) adapted to be positioned outside the housing and shielded against electromagnetic radiation, in particular sunlight. An arc detection system (43) according to any one of claims 12 to 16, comprising a sealed feedthrough (30) configured to allow the at least one light transmission means (55) to pass through the housing (3) of a transformer (1). An arc detection system (43) according to any one of claims 12 to 17, characterized in that the first portion of the at least one light transmission means (45, 55a) is at least 0.5 meter long. An arc detection system (43) according to any one of claims 12 to 18 in conjunction with claim 16, characterized in that the second portion of the at least one light transmission means (55b) is at least 0.5 meters, preferably 5 meters long. Arc detection system (43) according to any one of claims 12 to 19, characterized in that the light detector (47) is one of the following: semiconductor-based photosensitive sensors, in particular a photodiode, an avalanche photodiode, a phototransistor, a photoresistor, a CCD sensor, an APS-CMOS sensor, a pyroelectric sensor or a vacuum tube-based photosensitive sensor, in particular a photomultiplier or a photocathode.Power transmission device, in particular s rectifier transformer or a phase shifter or a choke coil with an arc detection system according to any of claims 12 to 20. Method for detecting an arc in a transformer (1) according to any one of claims 1 to 11 , comprising the steps of detecting electromagnetic radiation transmitted to the light detector (47) by the light transmission means (45, 55), comparing the duration and / or the intensity of the electromagnetic radiation and / or the wave spectrum with one or more limit values, and initiation of protective measures in the transformer when one or more limit values are exceeded, in particular disconnection from the input power and / or opening of a drain valve (31) on the housing (3) and / or introduction of an inert gas, in particular nitrogen, via an inlet valve (33).