Optical detector for high voltage cable accessories and method for optically measuring discharge

Abstract

The present invention relates to an optical detector for a high voltage cable accessory. The present invention also relates to a monitoring system for detecting discharges in a high voltage cable accessory and a method for detecting and / or monitoring discharges occurring in an insulating part of such a high voltage cable accessory. According to the present invention, the optical detector detects radiation generated by a discharge of the high voltage cable accessory having a wavelength of radiation generated by the discharge.

Description

Technical Field

[0001] The present invention relates to an optical detector for a high voltage cable accessory, a monitoring system for detecting discharges in a high voltage cable accessory, and a method for detecting and / or monitoring discharges occurring in an insulating part of such a high voltage cable accessory. Background Art

[0002] High-voltage cable accessories are used to connect high-voltage power cables to electrical equipment such as overhead lines, transformers, surge arresters, switchgear, etc. High-voltage cable accessories insulate or control the electric field of power cables under different environmental conditions and are expected to have a service life of more than 40 years without any failure. In order to achieve this requirement, the insulation system and its performance must be checked regularly. In addition, since installing terminals or installing cable joints always requires manual installation, failures during the installation process must also be considered. Such failures may cause electrical breakdown and subsequent arcing inside the terminal. Therefore, a diagnostic method is needed to provide information about the current status of cable accessories, including their remaining life.

[0003] The term "high voltage" as used hereinafter refers to voltages above about 1 kV. In particular, the term high voltage is intended to include the usual nominal voltage ranges for power transmission, namely medium voltage (about 3 kV to about 50 kV), high voltage (about 50 kV to about 110 kV) and extra-high voltage (currently about 500 kV). Of course, higher voltages may also be considered in the future. These voltages may be direct current (DC) or alternating current (AC) voltages. In the following, the term "high voltage cable" is intended to mean a cable suitable for carrying a current greater than about 1 A at a voltage above about 1 kV. Therefore, the term "high voltage accessory" is intended to mean a device suitable for connecting high voltage facilities and / or high voltage cables to each other. In particular, a high voltage cable accessory may be an end terminal or a cable joint.

[0004] The most common diagnostic method that provides real-time information about the condition and remaining life of cable accessories is partial discharge (PD) measurement. A discharge that does not completely bridge two electrodes or conductors in close proximity to each other is called a "partial" discharge. The term "partial discharge" used hereinafter is therefore intended to describe a short-term, low-energy and locally confined discharge within an insulation that irreversibly damages the insulation but does not lead to complete electrical breakdown. The term "partial discharge" is especially intended to include so-called "internal partial discharges" occurring within non-gaseous insulating materials. Originating from defects such as cavities or inclusions, and from interfaces with other materials, in particular with conductors carrying high voltages, partial discharges lead to the formation of "trees" that grow over time and ultimately lead to electrical breakdown. Such PD trees typically have a length of more than 1 μm.

[0005] The magnitude of such partial discharges is usually small, with the amount of charge transferred ranging from 10 to several hundred pico-Coulombs (pC). For partial discharge testing, a suitably high AC or DC voltage is applied to the conductor surrounding the insulation material being tested. Alternatively, depending on the defect and the energized system characteristics, the discharge can be detected under normal operating conditions.

[0006] Currently, the most common diagnostic method for obtaining the status of high-voltage cable accessories is the electrical partial discharge measurement according to IEC standard 60270 ("High-voltage test techniques - Partial discharge measurements", IEC 60270:2000). This setup mainly consists of a high-voltage source (which can be based on different technologies, such as standard 50 Hz or resonant systems), a coupling capacitor for signal extraction and a quadrupole to adapt the PD signal for direct measurement. During the treeing process, each partial discharge event generates a short-circuit current signal, which can be detected by the connected measurement equipment.

[0007] PD diagnostics are therefore based on the measurement of electrical signals of very small amplitude. A disadvantage of this technique is that, due to the small amplitude, it is very sensitive to electrical noise caused by external electric fields (e.g. from transformers, overhead lines, etc.). Therefore, partial discharge measurements in noisy environments (e.g. during field testing) do not always allow for a correct interpretation of the partial discharge measurements and therefore fail to provide insight into the condition of the high-voltage equipment.

[0008] Partial discharges also generate light, so partial discharges can be detected by measuring the light thus generated. This optical PD measurement is advantageously not affected by electrical noise from surrounding high voltage equipment. For example, by using fiber optic sensors integrated into high voltage accessories, real-time damage monitoring based on optical PC measurements can be achieved.

[0009] Such a fiber-optic sensor arrangement using fluorescent optical fibers is described, for example, in the article by WR Habel et al.: "Fibre-optic sensors for early damage detection in plastic installations of high-voltage facilities", XVII International Symposium on High Voltage Engineering, Hannover, Germany, August 22-26, 2011. A detailed description of the system is also given in the doctoral thesis "Dielectric strength behavior and mechanical properties of transparent insulation materials suitable to optical monitoring of partial discharges", published by Chaiyaporn Lothongkam from the Institute of Electrical Engineering and Computer Science at Gottfried Wilhelm Leibniz University Hannover, and similarly in the German patent application DE102010061607 A1 of February 2, 2014.

[0010] Another optical fiber sensor device is disclosed in European Patent Application No. 15173098.3. In European Patent 15173098.3, a field control element of a high voltage cable accessory comprises an electrically insulating material at least partially provided with a fluorescent dye. The fluorescent dye is configured to convert a first radiation generated by a discharge into a second radiation having a wavelength longer than that of the first radiation. An optical fiber is used to detect the second radiation.

[0011] Existing fiber optic sensor devices use fluorescence to shift the wavelength of radiation generated by partial discharges in optical fibers or field control elements attached to high voltage cables. Shifting the wavelength is necessary because conventional photodetectors are not sensitive enough to properly detect radiation from the discharge at its naturally occurring wavelength. However, the inclusion of fluorescent materials to achieve this shift may require the purchase or production of specific and expensive fluorescent optical fibers or fluorescent insulating materials. Summary of the invention

[0012] The object of the present invention is to overcome the disadvantages of existing solutions and to provide a sensitive, accurate and interference-resistant real-time monitoring of partial discharges in electrical insulators which can be produced more efficiently.

[0013] This object is solved by the subject matter of the independent claims. Advantageous embodiments of the invention are subject matter of the dependent claims.

[0014] The present invention is based on the idea that partial discharge detection can be more easily achieved by using an optical detector that can directly detect the radiation generated by the discharge with satisfactory sensitivity. In particular, the present invention proposes to provide an optical detector for a high-voltage cable accessory, wherein the optical detector detects the radiation generated by the discharge of the high-voltage cable accessory at the wavelength of the radiation generated by the discharge.

[0015] Advantageously, by using a sufficiently sensitive optical detector to directly detect the radiation generated by the discharge at the radiation wavelength, there is no need to provide an element capable of converting the radiation wavelength. Therefore, fewer components such as fluorescent materials or fluorescent dyes are required for accurate detection, and the optical detector and / or high-voltage cable accessories can be produced more efficiently and economically. The optical detector can be used with conventionally produced high-voltage cable accessories to accurately detect discharges. This results in simple installation of the optical detector and also allows easy and efficient replacement of components when necessary. In addition, since the detection principle is based on optical monitoring, it is not affected by electrical noise effects or corona. The embodiments of the invention described herein can also be used for all voltage levels (AC and DC).

[0016] According to the invention, the optical detector comprises an optical converter for generating an electrical signal from the detected radiation and an optical fiber for transmitting said radiation. The use of an optical fiber to generate an electrical signal from the detected radiation eliminates the effects of electrical noise. An advantage of providing an optical fiber and a separate optical converter is that the optical converter can be arranged in a protected environment outside the high voltage cable accessories and is therefore also not affected by electrical noise. The optical converter may comprise, for example, a photodiode to accurately convert the detected radiation into an electrical signal without increasing the necessary size of the optical detector.

[0017] The present invention also relates to a monitoring system for detecting discharges in high-voltage cable accessories. According to the invention, the monitoring system comprises a high-voltage cable accessory and an optical detector. As mentioned above, the term "high-voltage cable accessory" according to the invention means a device for connecting a high-voltage facility to a high-voltage cable or for connecting high-voltage cables to each other. In particular, the high-voltage cable accessory can be a cable joint or an end terminal. It comprises an insulating part, which in the installed state at least partially surrounds the cable insulation. As is known in the art, the insulating part generally comprises a field control element for controlling the electric field, so that an enhancement of the electric field due to charge accumulation can be avoided. To this end, the field control element comprises a region with a field grading material, which comprises, for example, a polymer matrix and a conductive organic filler forming a deflector of the field control element. Due to its geometric shape, the field control element of the high-voltage cable accessory is also often referred to as a "stress cone".

[0018] Such field control elements are at least partially made of polysiloxane materials, as described in detail in the doctoral thesis "Dielectric strength behavior and mechanical properties of transparent insulation materials suitable to optical monitoring of partial discharges" by Chaiyaporn Lothongkam of the Gottfried Wilhelm Leibniz Institute for Electrical Engineering and Computer Science in Hannover on July 25, 2014. Other materials are also used to manufacture the field control elements. Manufacturing the insulating field control body of the field control element from translucent or transparent polysiloxane allows sufficiently strong optical signals to be transmitted to the outside of the field control element.

[0019] The deflector of the field control element is conductive or semi-conductive and is located within an insulating field control body of the field control element so as to enhance the electrical noise immunity provided by the field control element. In one embodiment, the deflector is opaque and does not allow radiation generated by the discharge to pass through the deflector so as to limit the necessary area of ​​the field control element for detecting radiation from the discharge.

[0020] According to the invention, the optical detector is formed to be mechanically and optically coupled to the field control element for optimal detection of radiation. The field control element may have one or more openings for introducing an optical fiber. Alternatively, the optical fiber may also be arranged on the outer surface of the field control element, or the optical fiber may be partially embedded in the field control element and partially arranged on the outer surface. The sensing area of ​​the optical fiber is positioned along the path of the emitted light that does not intersect the deflector so as to directly detect the radiation of the emitted light.

[0021] The invention also relates to a method for detecting and / or monitoring discharges occurring within the insulating part of a high voltage cable accessory. The method comprises optically sensing radiation generated by the discharge of the high voltage cable accessory at the wavelength of the radiation generated by the discharge. In particular, the discharge can be adequately detected without providing an element capable of transforming the wavelength of the radiation. In one embodiment, the method is capable of detecting radiation having a wavelength below 400 nm to obtain optimal sensitivity and accuracy in detecting and / or monitoring the discharge. Furthermore, the method for detecting and / or monitoring the discharge can of course also be used for devices other than cable accessories. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are incorporated into and form a part of the specification to illustrate several embodiments of the present invention. These drawings, together with the specification, are used to explain the principles of the present invention. The drawings are only for the purpose of illustrating how to make and use the preferred and alternative examples of the present invention, and should not be interpreted as limiting the present invention to only the illustrated and described embodiments. In addition, according to the present invention, several aspects of the embodiments may form solutions individually or in different combinations. Therefore, the embodiments described below may be considered individually or in any combination. As shown in the accompanying drawings, further features and advantages will become apparent from the following more specific description of various embodiments of the present invention, in which the same reference numerals refer to the same elements, and in which:

[0023] Figure 1 is a schematic diagram of a known high voltage outdoor terminal;

[0024] Figure 2 is a schematic diagram of another embodiment of a known high voltage outdoor terminal;

[0025] Figure 3 is a schematic diagram of partial discharge in a field control element of a known high voltage outdoor terminal and radiation from the partial discharge;

[0026] Figure 4 is a schematic diagram of an optical fiber of an optical detector according to an embodiment of the present invention, which is located on a field control element to detect radiation from a partial discharge;

[0027] Figure 5 is a schematic diagram of a monitoring system according to the present invention having an optical detector positioned to detect radiation from partial discharges in a high voltage outdoor terminal. DETAILED DESCRIPTION

[0028] Figure 1 A known high voltage outdoor terminal 100 is shown which is commonly used for overhead lines. The terminal 100 provides a cable 102 with a cable lug 104 for connecting the cable 102 to, for example, a high voltage facility. In some embodiments, the outdoor terminal 100 is mounted on a substrate 106. In one embodiment, a housing 108 which may be made of porcelain surrounds the internal components of the terminal 100 and protects the internal components from the surrounding environment. In other embodiments, the housing 108 may be made of a silicone material.

[0029] The high voltage cable 102 inserted and connected in the cable terminal 100 is usually stripped of its outer layers in the cable terminal 100. The outer layers of the cable 102, such as the cable jacket, buffer layer, insulation layer and metal shield, can all be stripped from a portion of the cable 102 to expose the conductors 110 of the cable 102 in the terminal 100. Figure 1In the terminal 100 shown, the semiconductive outer cable shield 112 of the cable 102 remains on a portion of the cable 102 within the housing 108, and at least the transition portion between one end of the stripped outer cable shield 112 and the conductor 110 is surrounded by the field control element 120 of the terminal 100.

[0030] As is generally known in the art, there is an insulating region 118 within the housing 108 that is filled with an electrically insulating filler. In various embodiments, the insulating filler in the insulating region 118 may include a gas, such as air or sulfur hexafluoride (SF6), or a liquid, such as oil. In the illustrated embodiment, the insulating region 118 is substantially cylindrical and rotationally symmetrical.

[0031] Field control elements 120, also referred to as stress cones, are provided to control the electric field at the transition between the conductors 110 of the cable 102 and other outer layers of the cable 102. The field control elements 120 are arranged at a location within the insulating region 118 where the electric field stress would be too high to be insulated by the insulating filler within the insulating region 118 alone.

[0032] like Figure 1 As shown, the field control element 120 includes an insulating field control body 122 and at least one conductive or semi-conductive deflector 124. The deflector 124 is suitable for controlling the electric field and affecting the electric field distribution within a high-voltage cable accessory such as a terminal 100. In one embodiment, the field control body 122 is formed of a transparent or translucent elastic material, and the deflector 124 is integrated in the field control body 122. The field control body 122 can be formed of electrically insulating polysiloxane. In one embodiment, the field control element 120 is formed as a cone with an integrated deflector 124, which is formed to deflect the electric field lines by geometric / capacitive effects so that the field strength outside the field control element 120 is reduced to a non-critical value. The field control element 120 is formed with an internal hollow cylindrical opening for receiving the cable 102. The size of the internal hollow cylindrical opening can be formed to be suitable for a press fit between the cable insulator of the cable 102 and the field control element 120.

[0033] Figure 2 Another embodiment around a field control element 120 of a known high voltage outdoor terminal 100 commonly used for overhead lines is shown in more detail. Figure 2 In the illustrated embodiment, the cable inner insulation layer 114 remains within the field control element 120 and around the conductors 110 of the cable 102 within the terminal 100. A fiberglass layer 116 is located inside the housing 108 and surrounds the insulating region 118 with an insulating filler. The fiberglass layer 116 provides additional resistance to external electric fields. Figure 2The deflector 124, shown in more detail in FIG. 1 , can be formed from an opaque conductive or semiconductive material that is substantially impermeable to optical radiation.

[0034] Now refer to Figure 3-5 The present invention is explained in more detail.

[0035] Optical partial discharge detection is based on the detection of light generated by the physical breakdown process during the discharge. The wavelength of the generated light depends on the insulating material in which the discharge occurs. The discharge behavior is different for the three main groups of insulating materials used in high voltage engineering: air, oil and SF6. The wavelength range of discharges in air is partly in the ultraviolet region, typically below 475 nanometers. In one embodiment, the wavelength range of discharges in air is below 400 nanometers. Discharges in oil result in the emission of radiation with a wavelength range from about 380 nanometers to about 750 nanometers. Discharges occurring in SF6 produce radiation with a wavelength range from 380 nanometers to about 800 nanometers.

[0036] In solid materials, most discharges are associated with air discharges because voids contain air or faults are often caused by air entrapment. Partial discharges often occur in the stress cone of the terminal 100 or in the area of ​​the field control element 120, which may be due to improper installation of the field control element 120 or defective termination of the cable 102 within the terminal 100 causing air entrapment. Discharges may also occur in other areas, such as discharges in oil due to moisture entering the insulation area 118. The characteristic wavelength of radiation from partial discharges in plastic insulators (such as the field control body 122 of the field control element 120) can be assumed to correspond to the wavelength of discharges in air.

[0037] Figure 3 1 shows a typical emission of optical radiation of a partial discharge in a field control element 120. As described above, the discharge source 210 typically occurs due to trapped air at the field control element 120 and as Figure 3 As shown, the discharge source 210 is usually located in the portion of the field control body 122 adjacent to the electric field concentration of the conductor 110. The discharge source 210 is also usually located near the deflector 124 due to being close to the end of the outer cable shield 112 of the cable 102. Of course, the discharge source 210 can also appear in other parts of the field control body 122 and the field control element 120; Figure 3 The location of the discharge source 210 shown is exemplary only.

[0038] like Figure 3 As shown, when a partial discharge occurs, emitted radiation 220 in the form of light travels along a plurality of emitted light paths in all radial directions extending from the discharge source 210. The emitted radiation 220 passes through the transparent or translucent elastic material of the field control body 122. Figure 3As shown, the path of the emitted radiation 220 that intersects the insulator 114 within the cable or other portions of the cable 102 is blocked and cannot pass through the cable 102. Similarly, in the illustrated embodiment, the path of the emitted radiation 220 that intersects the deflector 124 is blocked by the opaque deflector 124 and cannot continue through the field control element 120.

[0039] At least one path of the emitted radiation 220 passes unimpeded through the field control volume 122 and is Figure 3 Emission region 230 is shown reaching the outer surface of field control volume 122. As described in more detail below, an optical detector may be located at emission region 230 to detect and / or monitor the occurrence of a discharge by receiving emission radiation 220 from discharge source 210.

[0040] like Figure 4 and 5 As shown, the optical detector according to the present invention comprises an optical fiber 310 adapted to transmit radiation and an optical converter 320 connected to the optical fiber 310, the optical converter 320 being adapted to receive radiation from the optical fiber 310 and to generate an electrical output signal from the radiation optical signal. In the embodiment shown, the optical fiber 310 is a polymer optical fiber (POF).

[0041] like Figure 4 As shown, the discharge source 210 corresponding to the occurrence of partial discharge can occur at multiple locations within the field control body 122, and each discharge source emits radiation 220, which passes through the field control body 122 and reaches the outer surface of the field control body 122 at one of the multiple emission regions 230. The optical fiber 310 has a sensing region that is mechanically and optically coupled to the field control element 120 at the emission region 230 to detect the emitted radiation 220 from the discharge source 210. The sensing region of the optical fiber 310 is located along the path of the emitted radiation 220 that does not intersect the deflector 124.

[0042] exist Figure 4 In the illustrated embodiment, the sensing region of the optical fiber 310 is partially located on the outer surface of the field control body 122 and partially embedded in the field control body 122. Figure 4 In an embodiment, the sensing region of the optical fiber 310 is circumferentially wound relative to the outer surface of the field control body 122 in a direction substantially perpendicular to the longitudinal axis of the field control element 120. The field control body 122 may have one or more openings for receiving the sensing region of the optical fiber 310, however, the optical fiber 310 must be disposed in the field control body 122 without gaps to avoid the optical detector itself becoming a source of partial discharge.

[0043] exist Figure 5In the illustrated embodiment, the sensing region of the optical fiber 310 is substantially entirely located on the outer surface of the field control volume 122 and extends parallel to the longitudinal axis of the field control element 120. In other embodiments, the sensing region of the optical fiber 310 may be entirely embedded in the field control volume 122, or any portion of the sensing region of the optical fiber 310 may be embedded in the field control volume 122 or located on the outer surface of the field control volume 122. In addition, the sensing region of the optical fiber 310 may extend in any direction relative to the longitudinal axis of the field control element 120. All embodiments of the optical fiber 310, regardless of the particular type of mechanical coupling device, have a sensing region that is mechanically and optically coupled to the emission region 230 of the field control element 120.

[0044] In another embodiment, to ensure optical reflection between the field control body 122 and the optical fiber 310, a separate layer with optically optimized reflection properties can be provided at the interface between the two surfaces. In another embodiment, the optical detector can include a photodetector arranged directly at the field control body 122 of the field control element 120.

[0045] The monitoring system 400 according to the present invention is Figure 5 As shown in FIG. 1 , the system includes an optical detector coupled to a high voltage outdoor terminal 100. The sensing area of ​​the optical fiber 310 is Figure 4 The emission region 230 of the field control element 120 shown collects the emission radiation 220 and transmits the radiation 220 to the optical fiber 310 via the portion other than the sensing region. Figure 5 An optical converter 320 is shown.

[0046] In one embodiment, the optical transducer 320 is a photodiode for converting the radiation 220 received from the optical fiber 310 into an electrical signal. In another embodiment, the optical transducer 320 may be a charge coupled device (CCD). The electrical signal generated by the transducer 320 may be further processed by a central monitoring unit (not shown) of the optical detector, which is configured to monitor the electrical signals transmitted from, for example, a plurality of such transducers 320.

[0047] According to the present invention, optical transducer 320 is sensitive enough to accurately convert detected radiation 220 having very short wavelengths. In one embodiment, optical transducer 320 is capable of accurately converting detected radiation 220 having wavelengths below 400 nanometers into electrical signals for analyzing partial discharges in field control element 210.

[0048] The optical detector according to the present invention is therefore able to directly detect and monitor radiation generated by a discharge in the air, or equivalently, a discharge in the field control body 122 of the field control element 120. Therefore, according to the present invention, it is not necessary to shift the wavelength of the emitted radiation 220 to a larger wavelength in order to detect and monitor the discharge in real time. Advantageously, the elimination of the necessary wavelength shift eliminates the need for additional shifting elements (such as fluorescent materials), thereby simplifying production and enabling the optical detector to be used with known high voltage cable accessories. In addition, the detection of the emitted radiation 220 at its naturally occurring wavelength improves accuracy by avoiding the loss or distortion of any detected characteristics of the emitted radiation 220 during the conversion to a longer wavelength. The use of the optical detector further eliminates the effects of electrical noise on the detection of the emitted radiation 220.

[0049] The present invention is described above with reference to a high voltage cable accessory in the form of a high voltage outdoor terminal 100. The terminal 100 is merely exemplary and the present invention is not limited thereto; the optical detector and monitoring system 400 of the present invention is equally applicable to switchgear terminals designed to be installed in a cable entry housing of a gas insulated switchgear, high voltage cable joints suitable for connecting two cables together, transformer terminals, and other types of high voltage cable accessories known to those of ordinary skill in the art. In addition, the optical detector and monitoring system 400 is applicable to a range of possible high voltages and can be used for all voltage levels. The optical detector and monitoring system 400 disclosed herein can be used with any enclosure having a stress cone or field control element and in which partial discharge may occur.

[0050] Description of Reference Numerals

[0051] 100 High voltage outdoor terminal

[0052] 102 Cable

[0053] 104 Cable lug

[0054] 106 substrate

[0055] 108 Housing

[0056] 110 Cable conductor

[0057] 112 External cable shield

[0058] 114 Cable Insulator

[0059] 116 Fiberglass Layer

[0060] 118 Insulated area with insulating filler

[0061] 120 Field control elements

[0062] 122 Field Control Body

[0063] 124 Deflector

[0064] 210 Discharge Source

[0065] 220 Emitted Radiation

[0066] 230 Launch Area

[0067] 310 Fiber

[0068] 320 Optical Converter

[0069] 400 Monitoring System

Claims

1. A monitoring system for detecting a discharge (210) in a high voltage cable accessory (100), the system comprising: High voltage cable accessories (100), and An optical detector, wherein the optical detector comprises an optical converter (320) which detects radiation (220) generated by a discharge (210) of a high voltage cable accessory (100) at a wavelength of the radiation (220) generated by the discharge (210), wherein the wavelength of the radiation (220) is not shifted, and wherein the radiation (220) has a wavelength range from 380 nm to 800 nm, wherein the optical transducer (320) generates an electrical signal from the detected radiation (220), and wherein the optical detector further comprises an optical fiber (310) for transmitting the radiation, The high voltage cable accessory (100) comprises a field control element (120), wherein the field control element comprises an insulating field control body (122) and a deflector (124) arranged in the insulating field control body (122); and The optical fiber (310) has a sensing region, which is partially located on the outer surface of the insulating field control body (122). Wherein, the optical fiber (310) does not have fluorescent dye.

2. The monitoring system according to claim 1, wherein: The optical converter (320) includes a photodiode.

3. The monitoring system according to claim 1 or 2, wherein: The insulating field control body (122) includes at least one portion of translucent or transparent polysiloxane.

4. The monitoring system according to claim 1 or 2, wherein: The deflector (124) is conductive or semi-conductive and opaque.

5. The monitoring system according to claim 1 or 2, wherein: Neither the field control element (120) nor the optical detector has a fluorescent dye.

6. The monitoring system according to claim 1 or 2, wherein: The sensing region is at least partially embedded in an insulating field control body (122).

7. The monitoring system according to claim 1 or 2, wherein: The sensing region of the optical fiber (310) is located along a path of the emitted radiation (220) that does not intersect the deflector (124).

8. The monitoring system according to claim 1 or 2, wherein: The high voltage cable accessory (100) is formed as an end terminal or a cable joint.

9. A method for detecting and / or monitoring a discharge (210) occurring in an insulating field control body (122) of a high voltage cable accessory (100), wherein: The method comprises optically sensing radiation (220) generated by a discharge (210) of a high voltage cable accessory (100) by an optical converter (320) detecting the radiation (220) at a wavelength of the radiation (220) generated by the discharge (210), and transmitting the radiation through an optical fiber (310), wherein the wavelength of the radiation (220) is not shifted, and wherein the radiation (220) has a wavelength range from 380 nm to 800 nm, wherein the optical converter (320) generates an electrical signal from the detected radiation (220), The high voltage cable accessory (100) comprises a field control element (120), wherein the field control element comprises the insulating field control body (122) and a deflector (124) arranged in the insulating field control body (122); and The optical fiber (310) has a sensing region, which is partially located on the outer surface of the insulating field control body (122). Wherein, the optical fiber (310) does not have fluorescent dye.

10. The method according to claim 9, wherein: The radiation (220) has a wavelength below 400 nanometers.

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