A cleaning device for an insulator disc

Abstract

The cleaning device 100 includes housings 114 configured to be securable to the power cable with a wind turbine and an ultra-violet radiation sensing system 116 associated with the housings. The wind

Description

The invention relates to a cleaning device for an insulator disc on a power cable or line. BACKGROUND TO THE INVENTION High-voltage transmission lines are used in electric power transmission and distribution to transmit electricity across large distances. These lines are bare conductors, and a high level of insulation from the transmission tower is required for safety. The insulation between the high-voltage line conductor and the transmission tower is generally provided by insulator discs. The performance of these insulator discs depends not only on the material from which the discs are made but also on environmental factors. Pollutants and dust particles like coal, sand, and salt deposits accumulate on an insulation disc's surface, affecting the insulation efficiency. The electrical transmission lines that pass through industrial, desert, marine, or coastal areas are more disposed to air pollution factors. Additionally, surface biofouling affects the insulator disc’s performance because of microbial deposition, bird droppings, and biofilm formation. These accumulations create a conductive channel that may facilitate partial discharge, leakage current, flashover, and corona discharge and ultimately cause power transmission failure. Such types of faults can be reduced by regular cleaning of the insulator disc. Water is the best natural cleaner for these insulation discs. Manual cleaning of the discs is performed by an operator with a waterjet placed close to the transmission line. The spraying of the water not only requires a large amount of water, but manual spraying is also life-threatening. According to research published by the National Institute for Occupational Safety and Health of the United States, over 500 workers die annually in overhead power line cleaning-related accidents. Other methods of cleaning the discs may require periodic shutting down of the transmission line to the consumers, including hospitals, schools, and industrial areas. Research has advanced in power line cleaning solutions in the last few decades. CN112117062A discloses a suspension porcelain insulator with a housing around it. The housing provides a protective structure to which blades are mounted. Each blade is connected through a rod to a plurality of sponge pads that are arranged to clean the surface of the insulator discs upon rotation of the blades by the wind. When it rains, water is filtered through a conical filter cartridge and flows into a funnel which directs the water to a nozzle configured to spray the rainwater onto the umbrella skirts of the insulators. CN211088002 discloses a disc-shaped suspension porcelain insulator which has a shaft fixed to the top end of the insulator body. Two blades (wind power plates) are mounted to the shaft at the ends of an elongate brush. A water tank is provided above the shaft with drainpipes that direct collected rainwater towards the brush. The blades are blown by the wind to rotate the brush about the shaft so that the brush is driven across the surface of the insulator body to remove dust. The brush hair is wetted by the drainage pipe to improve the self-cleaning performance of the insulator. CN206774335U describes a self-cleaning insulator that includes an insulator body. The head end of the insulator body has an upper turntable, and the tail end of the insulator body has a lower turntable. The upper and lower turntables both have blades, and a support rod is connected between the upper turntable and the lower turntable with a plurality of brushes arranged on the support rod in an inclined state. In use, the wind blows the blades, and the blades drive the upper turntable and lower turntable to rotate. The support rod and brushes rotate with the turntables to remove dirt from the surface of the insulator body. CN105067909B discloses a robot with a crawling mechanism and claws for moving between insulators and includes both a detection module for detecting distributed voltages of an insulator and a cleaning module for cleaning the insulators. The detection module includes firstand second detectors arranged to be in contact with the steel foot and cap of the insulator for distributed voltage collection. The cleaning modules on the upper and lower frame include a rotating brush that can be steered via a brush steering mechanism. While research in the field of insulator disc cleaning has advanced, there remains a need for a simple and cost-effective device to safely clean debris from insulation discs to minimise discharge events. The preceding discussion of the background to the invention is intended only to facilitate an understanding of the present invention. It should be appreciated that the discussion is not an acknowledgment or admission that any of the material referred to was part of the common general knowledge in the art as at the priority date of the application. SUMMARY OF THE INVENTION In accordance with an aspect of the invention there is provided a cleaning device for an insulator disc on a power cable comprising: a housing configured to be securable to the power cable; a wind turbine associated with the housing and having a blade with an adjustable brush attached thereto, the adjustable brush being configured to abut against the insulator disc to clean the disc upon rotation of the wind turbine; and a sensing system associated with the housing and configured to sense electric discharge events. The blade may have grooves configured to receive water from the surrounding atmosphere. The grooves may have pockets configured to further collect and retain water from the atmosphere. The blade may include or support a water storage container in fluid communication with the brush for storing water to be used for wet cleaning of the insulator discs. The grooves on the blade may be in fluid communication with the water storage container to direct the water collected from the atmosphere to the storage container. The blade may be coated with hydrophilic and hydrophobic coatings, the hydrophilic coatings being on the inner surfaces of the grooves and the hydrophobic coatings on the exterior surfaces next to the grooves on the blade. The brush may include an arm with a spring providing a bias in the direction of a brush head hingedly connected to the arm. The sensing system may include an electric discharge detection sensor. The sensing system may further include a controller configured to be in communication with the electric discharge detection sensor to continuously monitor for electric discharge events. The wind turbine may be configured to electrically power the sensing system. The wind turbine may include a rotatory mechanism including a pair of magnets arranged such that magnetic repulsion between similar poles of the magnets reduces friction upon rotation of the wind turbine. The rotary mechanism may be in a housing to substantially avoid interference of the magnets with an electromagnetic field of high voltage lines. The elongate blade may be modular and include a plurality of blade members that are releasably attached to one another, each blade member having an adjustable brush secured thereto for cleaning an insulator disc opposite the brush. The blade members may be releasably attached to one another via complementary male and female mating formations. Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: Figure 1 is a three-dimensional view of an embodiment of the cleaning device; Figure 2 is a top view of an embodiment of the cleaning device; Figure 3 is a three-dimensional view of a blade and an enlarged view of the surface of the blade; Figure 4 is a three-dimensional side view of a section of the blade surface; Figure 5 is a three-dimensional view of a blade before and after engraving; Figure 6 is a schematic diagram of airflow through the grooves; Figure 7 is a three-dimensional view of an embodiment of the housing of the cleaning device in assembled and disassembled conditions; Figure 8 is a schematic diagram of the magnetic rotary mechanism viewed from the top; Figure 9 is a three-dimensional side view of an embodiment of a cleaning brush assembly; Figure 10 is a side view of complementary male and female mating formations; Figure 11 is a top view of blades with different male formations; Figure 12 is a three-dimensional side view of an embodiment of lugs on a blade; Figure 13 is a graph comparing dry and wet cleaning and its effect on the insulator disc efficiency; Figure 14 is a flow diagram of the different systems that form part of the cleaning device; and Figure 15 is a block diagram of the parts of the sensing system. DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS An insulator disc cleaning device is provided that is mountable to a power cable near an insulator disc. The device includes a housing configured to be securable or mountable to the power cable. A wind turbine is associated with the housing and includes one or more brushes attached to blades of the wind turbine for cleaning the insulator disc upon rotation of the blades. The wind turbine is also configured to harvest energy from wind to generate electricity. The device further includes a sensing system or module that is associated with the housing and configured to sense electric discharge events near the insulator discs. The wind turbine converts kinetic energy from the wind into electrical power which may be used to power the sensing system in some embodiments. The cleaning device may further include a water-harvesting system configured to passively harvest water from the atmosphere and direct it to the brushes for use in cleaning the insulator disc. The wind turbine of the device includes at least one rotor blade with a brush attached thereto. The brush is configured to abut against an insulator disc to clean the disc upon rotation of the blade by wind. The brush is preferably adjustable in length or flexible but may also be fixed relative to the blade in some embodiments of the invention. The brush may for example include an arm or connector that includes a spring providing a bias in the direction of the brush head. The brush head in turn may be hingedly connected to the arm. The hinged brush head and biasing force from the spring ensures that the brush has a degree of adjustability and will remain against the surface of the insulator disc in use. Ideally several rotor blades and brushes form part of the cleaning device to improve cleaning efficiency. The surface of the blade may be smooth, but preferably includes grooves that are configured to collect moisture from the atmosphere. The grooves may be configured to form a network of passages for the collection of water on the blade surface. The grooves may further include pockets configured to assist in collecting and retaining water on the blades. The blade may have a water storage container in fluid communication with the brush. The grooves on the blade may be in fluid communication with the water storage container to direct the water collected from the atmosphere to the storage container. Alternatively, the grooves may direct the water directly to the head of the brush to assist in cleaning the discs. The blades may have internal water channels that transports the water from the surface of the blade to the arm of the brush. The arm of the brush may be hollow or define passages to allow water to flow through it to the brush head. The brush head may have water outlets to allow the collected water to drain onto the surface of the insulator discs to assist in cleaning the discs. The sensing system may include a sensor configured to detect electric discharge events in its vicinity whilst the housing that includes the sensing system is mounted at or near the insulator disc. Various sensors may be included in the sensing system such as optical sensors, ozone sensors, UV sensors and the like. The sensing system may include a controller configured to be in communication with the electric discharge detection sensor and any additional sensors that may be included to continuously monitor for electric discharge events detectable by the sensors. The wind turbine may be a vertical axis wind turbine by having blades extending generally vertically and between two separate housing parts that clip onto the power cable and over the insulator disc(s). The wind turbine may be configured to electrically power the sensing system. An alternative electrical power source may be provided to power the sensing system with the power generated by the wind turbine used for another purpose. For example, a solar panel may be mounted to or near the device and connected to the device to power the sensing system. An additional power source may also be used to rotate the blades and brushes in case there is no wind. The solar panel may be said additional power source. The wind turbine may include a rotatory mechanism involving a pair of magnets arranged such that magnetic repulsion between similar poles of the magnets reduces friction upon rotation of the wind turbine. The magnets may be in a housing configured to substantially avoid interference of the magnets with an electromagnetic field of high voltage power lines. An embodiment of the cleaning device (100) is shown in Figure 1. The cleaning device (100) is mounted to a high voltage power cable and substantially over a plurality of insulator discs (102) arranged coaxially in a stacked configuration on the power cable. The device includes two separate housing parts (114) arranged coaxially and spaced apart along the length of the power cable (120) the cleaning device (100) is mounted to. The housing parts (114) are each configured to clip onto the power cable to secure the cleaning device thereto. The cleaning device (100) has a wind turbine with at least three blades (104) extending parallel to the power cable and between the housing parts (114). The blades (104) are equally circumferentially spaced about the cylindrical housing parts (114) that they are attached to. The rotor blades (104) are shaped to harvest energy from the wind to rotate a generator. Any number of rotor blades may form part of the wind turbine. In the embodiment of Figure 1, three blades are arranged 120° apart about the insulator discs (102). At least one arm (106) or connector with a brush (108) at its free end extends generally transversely from each blade (104). In the embodiment of Figure 3, each blade (104) has three arms (106) and brushes (108) spaced along the length of the elongate blade (104). Each brush (108) is configured to abut against the insulator disc (102) to clean it upon rotation of the blade from wind. The curved brush heads (122) of the brushes (108) are each sized and shaped to span the distance between apex of the dome-shaped insulator disc (102) and its rim so that rotation of the blade results in the brush rotating about the circumference of the insulator disc to clean substantially the entire upper surface of the insulator disc (102). The brush head may comprise pivotally connected brush head elements to ensure that the brush head is adjustable and can be fitted to insulator disc surfaces with different curvatures. In the embodiment of Figure 1, each insulator disc is cleaned by three brushes, i.e., a brush extending from each blade. It will be appreciated that only one arm and brush per insulator disc is required. However, the multiple brushes of the embodiment shown in Figure 1 increases the cleaning efficiency. Therefore, it is preferred that the product of the number of blades and the number of insulator discs is equal to the number of cleaning brushes. The blades are connected to a hub (110) connected to the main shaft of a generator (not shown) of the wind turbine through support or link rods (112). In this manner the blades are connected to a generator to rotate an electromagnet of the generator and generate electricity. The generator includes a coil of conductive wires (stator), with the electromagnet rotating in the coil to induce a current. In the embodiment of Figure 1, the elongate blades (104) extend parallel to the main shaft of the generator. The generator may be housed within the hub (110) and / or housing (114). The configuration and orientation of the various wind turbine components such as the blades and the main shaft is similar to a vertical axis wind turbine which can generally capture wind from any direction. The rotary mechanism of the wind turbine may include one or more pairs of permanent magnets to create a magnetic levitation arrangement or support which reduces friction upon rotation of the wind turbine. The permanent magnet rotary mechanism may be placed inside a housing so that the magnets do not interfere with the electromagnetic field of the high voltage lines. The housing (114) may further contain a sensing system (116) for electric discharge detection. The sensing system may be capable of detecting electric discharge events such as partial discharges, leakage currents, flashovers, and corona discharges. The housing (114) is not limited to a cylindrical shape and may be any suitable shape and size. The device may also include a water harvesting mechanism. Each turbine blade may have grooves (118), arranged in a bioinspired pattern to harvest water in the atmosphere. The grooves (118) may include pockets or indents may be defined within the grooves. The size and shape of the pockets are selected such that the wind turbine's efficiency will be least affected by the weight of the water in the pockets and its variation. The water pockets are configured to minimise the loss of water due to centrifugal force during the rotation of the turbine. Each blade may contain one or more water storage containers (125) which are in fluid communication with the cleaning brush (108). The water pockets may be connected to the water storage containers (125) through the grooves (118) that act as water channels. The width of the grooves may be selected so that it allows the minimum quantity of water to be received within the grooves that is required for cleaning. The blades may be coated with hydrophilic and hydrophobic layers to accelerate the water harvesting mechanism. The hydrophilic coatings may be on the inner surfaces of the grooves and the hydrophobic coatings on the exterior surfaces next to the grooves so that the water tends to collect in the grooves. The inner hydrophilic coating contains hydroscopic or hydrophilic substances that are capable of passively harvesting water from the atmosphere. The materials used for the coating may be metal-organic frameworks, hygroscopic inorganic compounds (and derivative materials), or functional hydrogels, for example. The bioinspired grooves or patterns may further enhance the water harvesting efficiency. The hydrophobic layer which may be formed of a hydrophobic polymer coating or the like on the exterior surfaces surrounding the grooves tends to fuse and form droplets and direct the harvested water towards the water pockets through its water-repelling nature. Figure 2 shows a top view of the cleaning device (100). The top view of the turbine blades (104) demonstrates the rotational direction (shown with arrows) of the turbine. The rotation is represented by a circular dotted line (123). The top view shows the shape of the airfoils of the blades. The airfoils are not limited to the NACA profile and different airfoils may be used depending on the application. Figures 3 and 4 show an enlarged view of the blade surface. The blade’s surface may be engraved with bio-inspired water-harvesting grooves (118) for receiving water from the atmosphere. Water pockets (124) are arranged along these grooves to facilitate additional water retention on the blades. The water pockets (124) may be connected via the grooves that act as water channels that displaces the harvested water. The grooves may be configured to direct the water to a temporary storage container that ultimately directs the water to the head of the brush to optimize cleaning of the insulation discs. The grooves on the blade may be created by etching or engraving the pattern on the blade surface. There may be a difference in the weight of the blade before and after the engraving process. The weight of the cleaning blade after engraving may follow the given relation: Weight After Engraving Total Weight The total weight before engraving w is the sum of blade weight after engraving w± and weight of the material removed w’ as shown as: w =  + w' For the stability of the blade, after engraving, the grooves must follow the relation, Wi Constant = — w Constant < Yield strength of material To achieve optimal efficiency, the weight of the turbine should be close to the total weight before engraving. In the case where the weight is not constant, the variation of weight affects the turbine’s efficiency. During variation of weight, the same forces applied to the blades will get a different response from the blades. The solution to the problem is to design blades with a weight that is slightly less than the total weight before engraving and approaches this total weight in the presence of the harvested water. Two blade before and after engraving is shown in Figure 5. The one blade (119) does not have water on the surface of the blade (119) and the other blade (121) has water on the surface of the blade (121). The final weight of the blade in the presence of water balances out the total weight before engraving and increases efficiency. Wptnal ~ Before Engraving As shown in Figure 6, the grooves may allow air (represented by arrows in Figure 6) to pass through them. When the water pocket is empty, as shown in example A of Figure 6, air freely flows through the grooves which results in a decrease in the efficiency as the blade is less able to harvest wind energy by providing less resistance to the wind. When the water pocket is partially filled, as shown in example B of Figure 6, only a part of the air may pass through the grooves. The turbine is designed to provide optimal efficiency when the water pockets are fully filled with water, as shown in example C of Figure 6. The pressure experienced by the engraved area may be changed due to the geometrical changes of grooves when filled with water. The pressure PT experienced by the blades before engraving (119) and the pressure PT' experienced by the blade after engraving (121) and filled with water may be the same. PT = PT' The housing of the cleaning device is configured to be releasably securable to a live wire, preferably by comprising two half cylinders each having a central depression or furrow which defines a central passageway for the power cable and a clip or any other suitable complementary attachment formations on the half cylinders that are arranged to join them together over the cable. Figure 7 is a cross-sectional view of an embodiment of a cylindrical housing (114) which shows the inside of the housing is a hollow cylindrically shaped cavity containing magnetic arrangements for rotation. The housing is located at the top and bottom of the cleaning device to attach the cleaning device to the wires and isolation discs. The top section (114a) of the housing may carry a sensor box which may contain the sensing module (116) for electric discharge detection and monitoring, as well as the generator of the wind turbine. The lower two sections (114b, 114c) may contain the two sets of magnets. One magnet may act as the rotor and the other as the stator. The magnetic rotary mechanism is enclosed in the housing (114) in order not to interfere with the external electric fields. Figure 8 shows the magnetic rotary mechanism and demonstrates the magnetic arrangement of repulsion between the rotor (128) and stator (126) that may assist in the rotation of the wind turbine of the cleaning device. One set of magnets may act as a stator (126) placed in the centre of the magnet configuration. The second set of magnets may act as a rotor (128) and may be placed around the stator magnets. Any suitable number and size of magnets may be used for the stator and rotor, for example the stator magnets may be smaller in relation to the rotor magnets. The two sets of magnets are placed at a selected distance (130) from each other which may be chosen dependant on the type, size and shape of the magnets and other system requirements. The magnetic repulsion along with the kinetic energy from the wind will allow the turbine to rotate even at low wind speed. An embodiment of the adjustable brush is shown in Figure 9. The arm (106) or connector of the adjustable brush (108) includes an internal spring (132). The arm (106) may be telescopically adjustable or include a telescopically extendable portion along its length to vary the length of the arm. The spring providing a bias in the direction of the insulator discs allows for a degree of movement of the brush head relative to the blade that the arm is secured to. The brush head (122) of the brush assembly (108) may be hingedly connected to the arm (106) by an adjustable screw (134). The brush head may also include hinges or adjustable screws (134) which provides an additional degree of freedom to the brush assembly. Due to the adjustable nature of the brush assembly, the cleaning device may be used to clean different sizes of insulator discs. The brush fibres (136) that assist in cleaning may be made of soft insulating material which may not produce friction and scratches on the surface of the disc insulator. The brush fibre (136) can be coated with a nanolayer of hydrophobic material which provides the brush with the ability to self-clean. The cleaning device is configured to be modular with the blade and brush assembly of the cleaning device configured to releasably attach to and stack on each other to accommodate and clean a larger number of insulator discs. As shown in Figure 1, several blade members and brushes may be stacked together to function as a large single device. In the embodiment shown in Figure 1, the cleaning device is designed for three insulator discs. For higher voltages the number of discs may increase, and accordingly more blade members and brushes may be needed. To connect the blade and brush assemblies to each other, the edges of the blades (104) may have complementary male and female mating formations or lugs (140) and sockets (138) configured to fit into each other as shown in Figures 10 to 12. Regardless of the number of blade and brush assemblies required, only a single top and bottom housing is required. Four different shapes of male formations or lugs (140) are shown in Figure 11. The round lug (140a) is the simplest design out of all four shapes but due to its circular shape the blades may rotate along the axis of the lug which may lower the overall efficiency of the system. This problem may be reduced by changing the lug shape to a square (140b). The preferred lugs are oval shaped (140c) or have two circular lugs (140d). The oval shape may result in less air friction than the other lug shapes. The oval lug (140c) is shaped according to the shape of the airfoil but has a larger area than the circular shaped lug (140a), which increases air friction. The area of the lug may be decreased by using two circular lugs (140d). The exposed lugs that are not connected to another blade and that protrude from the operatively upper or top blade may affect the aerodynamics of the blades as shown in Figure 12. The air vectors (142) may have little effect if the radius of the lug (140d) is small. These small extrudes are designed such that they may withstand the air pressure. While the cleaning device works optimally with water, it may also function without it. The comparison of dry and wet cleaning and its effect on the insulator disc efficiency and flashover voltage is shown in the graph of Figure 13. For dry cleaning (146), dust and salt deposits are removed but the grease and some organic waste may not be removed properly and consequently the insulator disc efficiency may decrease. On the other hand, wet cleaning (144) with water harvested from the air via the grooves removes grease and some organic dirt as well. Wet cleaning therefore increases the cleaning efficiency and may increase both the insulator disc performance and its flashover voltage. The sensing system may include a controller configured to be in communication with the electric discharge detection sensor to continuously monitor for electric discharge events. The controller may be configured to record electric discharge events and may include a signalling component for signalling that an electric discharge event occurred and / or is happening. The controller may be configured to be in communication with an external computer to transmit a signal to the external computer (preferably through wireless communication) when an electric discharge event is sensed by the electric discharge sensor. The controller may include a warning component such as an alarm or be configured to transmit a warning signal to the external computer when a discharge event is sensed by the electric discharge sensor. A system flow diagram is illustrated in Figure 14. The wind turbine or energy harvesting system (210) produces energy from the rotation of the blades. The power from the turbine may be managed by a power management system (220), which drives a digital signal processor (DSP) unit (250) and Internet of Things (loT) electronics (230). The power management system may act as a type of control system that monitors the power flow within the energy harvesting system to ensure safe operation. The power management system may include electronic circuitry components like controllers, drives, and regulators that monitor the power flow and regulate the amount of required power. Primarily, the power is generated from the turbine rotation but in case of extreme wind or hazardous weather conditions, the power management system may manage the operation to protect the energy harvesting system. The power management system (220) may be linked with the sensing system (116) and loT electronics system (230). The sensing system (116) which may contain different sensors sends the data to the DSP unit (250). The DSP (250) may communicate with the cloud (240) via the loT electronics system (230). When the detected electric discharge value of any of the sensors rises beyond a threshold value, a signal may be sent to an alarm (260) by the DSP unit (250). The block diagram of Figure 15 shows parts of the sensing system (116). The sensing system (116) may comprise optical sensors (310), ozone sensors (320), UV sensors (330), and other similar and suitable sensors (340) configured to detect electric discharge events. The sensing system may be powered by the energy harvested from wind by the rotation of the turbine of the cleaning device. During corona discharge some physical changes occur i.e., bluish light, hissing sounds, UV flashes, and ozone emission. These physical changes may be detected by the one or more sensors of the sensing system or module to monitor the insulation discs. The sensing system may also monitor signs of a possible future discharge event provided it includes suitable sensors. If the sensing system is linked with an loT electronic system that sends data to the DSP unit via the cloud, the sensing system may signal a possible future discharge event and allow intervention to prevent it from future complications. UV sensors (330) may be used to detect the presence of UV around the insulator or conductor, but this may not be sufficient during the day. The UV sensor may be replaced by a UV camera that can transmit images for image processing or can process the images itself. In addition, optical sensors (310) may be installed to detect violet-bluish discharge which may happen during corona discharge. The ozone sensor (320) detects the concentration of ozone in surrounding air. If the ozone exceeds a threshold level associated with an electric discharge event near the sensor, the ozone sensor may be configured to send a signal or the information to an external computer or the cloud. Different sensors may form part of the sensing system depending on the requirements. To detect electric discharges an electric discharge detector may be installed. The present disclosure may provide a low-cost, self-sustained insulator cleaning device. Embodiments of the present disclosure may have applications including, but not limited to, high voltage engineering, power transmission and distribution, substation maintenance, electric discharge monitoring, dielectrics and composite materials, and related fields. Advantageously, the cleaning device described herein is configured to harvest wind to simultaneously clean insulator discs and to power a sensing module for sensing electric discharge events that may signal that further cleaning or maintenance is required. The foregoing description has been presented for the purpose of illustration; it is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above disclosure. For example, while the device has been described to be fitted to insulator discs, in another embodiment, the insulator discs may be part of the device i.e., a self-cleaning insulator disc assembly is provided which comprises a set of insulator discs and the cleaning device described herein assembled together with the assembly configured to be mountable to a power cable. The language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based hereon. 5 Accordingly, the disclosure of the embodiments of the invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims. Finally, throughout the specification and accompanying claims, unless the context requires otherwise, the word ‘comprise’ or variations such as ‘comprises’ or ‘comprising’ will be understood 10 to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims

1. A cleaning device for an insulator disc on a power cable comprising:a housing configured to be securable to the power cable;5 a wind turbine associated with the housing and configured to harvest kineticenergy from the wind and convert it into electrical power, the wind turbine having a blade with an adjustable brush attached thereto, the adjustable brush being configured to abut against the insulator disc to clean the disc upon rotation of the wind turbine; and10 a sensing system associated with the housing and powered by the electrical powerfrom the wind turbine, the sensing system being configured to detect electric discharge events which signal that further cleaning of the insulator disc or maintenance is required.

152. The cleaning device as claimed in claim 1, wherein the blade has grooves configured to receive water from the surrounding atmosphere.

3. The cleaning device as claimed in claim 1 or 2, wherein the blade includes a water storage container in fluid communication with the brush.

4. The cleaning device as claimed in claim 3, wherein the grooves on the blade are in fluid communication with the water storage container to direct the water collected from the atmosphere to the storage container.25 5. The cleaning device as claimed in any one of claims 2 to 4, wherein the blade is coatedwith hydrophilic and hydrophobic coatings, the hydrophilic coatings being on inner surfaces of the grooves and the hydrophobic coatings on exterior surfaces next to the grooves on the blade.30 6. The cleaning device as claimed in any one of the preceding claims, wherein thesensing system includes an electric discharge detection sensor selected from a UV sensor, an ozone sensor, or an optical sensor.

7. The cleaning device as claimed in claim 6, wherein the sensing system includes a 35 controller configured to be in communication with the electric discharge detectionsensor to continuously monitor for electric discharge events, the controller including asignaling component configured to signal that an electric discharge event occurred and that further cleaning or maintenance is required.5 8. The cleaning device as claimed in any one of the preceding claims, wherein the brushincludes an arm with a spring providing a bias in the direction of a brush head hingedly connected to the arm.

9. The cleaning device as claimed in any one of the preceding claims, wherein the wind10 turbine includes a rotatory mechanism including a pair of magnets arranged such thatmagnetic repulsion between similar poles of the magnets reduces friction upon rotation of the wind turbine.1510. The cleaning device as claimed in claim 9, wherein the rotary mechanism is in a housing to substantially avoid interference of the magnets with an electromagnetic field of high voltage lines.

11. The cleaning device as claimed in any one of the preceding claims, wherein the elongate blade is modular and includes a plurality of blade members that are releasably attached to one another, each blade member having an adjustable brush secured thereto for cleaning an insulator disc opposite the brush.

12. The cleaning device as claimed in claim 11, wherein the blade members are releasablyattached to one another via complementary male and female mating formations.25

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