CN111044895A

CN111044895A - State sensing method for open type isolating switch

Info

Publication number: CN111044895A
Application number: CN201911280883.5A
Authority: CN
Inventors: 姜杏辉; 童彬; 董巍
Original assignee: Suzhou Huadian Electric Co Ltd
Current assignee: Suzhou Huadian Electric Co Ltd
Priority date: 2019-12-13
Filing date: 2019-12-13
Publication date: 2020-04-21

Abstract

The invention relates to a state sensing method of an open type isolating switch, which is used for identifying the on-off state of the open type isolating switch, and comprises the following steps: and shooting a depth image of the open type isolating switch, and identifying the opening and closing state of the open type isolating switch based on the depth image to obtain an identification result. The invention can monitor the open-close state of the open-type isolating switch, and has the advantages of easy implementation, effectiveness, reliability, wide application range and the like.

Description

State sensing method for open type isolating switch

Technical Field

The invention belongs to the field of power equipment state monitoring and automatic control, and particularly relates to an open type disconnecting switch state sensing method for realizing remote rapid operation and intelligent operation and maintenance of equipment in a transformer substation.

Background

Switching operation is the most common type of operation in substation operation and maintenance work. With the development of science and technology, the switching operation starts to gradually transit to the 'one-key sequential control' mode. The one-touch control means that substation equipment is remotely controlled by programmed instructions at a remote place. Compared with the traditional field operation mode, remote operation is realized by one-key sequential control, and operation and maintenance personnel do not need to go to and fro between the transformer substations, so that the operation time is short, and the influence on a power grid is small; the programmed control is realized, so that the misoperation risk is small, the operation is simple, and the labor cost is greatly reduced. Therefore, one-key sequential control of switching operation is a development direction of future substations.

The switching operation generally changes the state of the device by opening and closing a circuit breaker and a disconnecting switch (knife switch). For the circuit breaker interval shown in fig. 1, the programmed operation logic is shown in fig. 2, taking the operation of changing the circuit breaker interval from running to cold standby as an example.

It can be seen that after each circuit breaker/disconnector action, it is necessary to confirm whether it is in place. This step is very important because there are cases where the breaker or the disconnector is rejected or is not in place theoretically, and if the next operation is performed without confirmation, serious misoperation accidents such as disconnecting and switching the knife switch with load may occur. In manual switching operations, the confirmation of the state of the circuit breaker and disconnector is usually done visually, whereas in the push-to-control mode this step needs to be done by other means.

For the circuit breaker, because its mechanical part is usually sealed, the operational environment is comparatively stable, and the probability that itself appears refusing action is lower, and because the circuit breaker action is usually along with the change of voltage current, can judge the deciliter state of circuit breaker comparatively easily through the voltage current on the monitoring line.

The isolating switch is divided into an open type (GIS) and a closed type (GIS). The operation of the GIS isolating switch is stable, and the state monitoring can be effectively performed by using a state sensing means, so that the discussion is omitted, and the following discussion is directed to an open isolating switch (if not particularly labeled, the isolating switch in the following text refers to an open isolating switch).

The number of the open-type disconnecting switches in the power grid is very large, the reliability under long-term operation is difficult to guarantee due to the fact that mechanical parts of the open-type disconnecting switches are exposed outside, the probability of the open-type disconnecting switches not being connected in place is relatively high, and the state change of the open-type disconnecting switches is usually not reflected by the voltage and current change of the circuit due to the fact that the open-type disconnecting switches are usually operated in a power-off state, and therefore the state sensing of the open-type disconnecting switches becomes the bottleneck of achieving one-key sequential control of the power.

At present, three methods for sensing the state of the isolating switch are mainly used:

1) auxiliary contact method

The auxiliary contacts on the operating mechanism of the isolating switch are a series of small switches linked with the knife switch contact, and when the knife switch is displaced, the auxiliary contacts are driven to be displaced. The displacement condition of the disconnecting link can be reflected by detecting the opening and closing condition of the auxiliary contact. The method has the advantages of extremely simple realization, no need of adding any auxiliary equipment, realization by directly utilizing the existing device, low cost and no influence on the inherent running state of the equipment.

However, the auxiliary contact method is only an indirect measurement method, and the accuracy of the result cannot be completely guaranteed. The field operation experience shows that the situation that the auxiliary node signal is inconsistent with the actual position of the disconnecting link due to mechanical reasons is common. For example, the auxiliary contacts may already be in the closed state when the contacts of the knife switch cannot be brought into position due to a mechanical failure. At this time, if power is transmitted, the knife switch contact may generate heat due to poor contact, and serious equipment damage or grid accidents may occur.

2) Pressure method

The contacts of the disconnecting switch are usually connected by plugging or pressing, and springs are usually arranged at the joints of the contacts to ensure the reliability of contact. A pressure sensor is arranged on the contact spring, and the opening and closing conditions of the isolating switch can be reflected by detecting the pressure change of the spring. The method has the advantages that the contact reliability of the knife switch contact can be directly monitored from a mechanical angle, and the contact heating problem caused by poor contact is avoided.

However, although the pressure sensor can better reflect whether the contact of the disconnecting switch after closing is reliable, the pressure sensor cannot reflect whether the opening process is in place. If the insulation distance is not enough due to the fact that the opening is not in place, the air gap between the contacts can be broken down, and serious equipment and personal accidents are caused. Meanwhile, the working environments of the pressure sensors installed on the isolating switch are outdoor, and the temperature and humidity difference and other environmental factors are large, so that the measurement result of the pressure sensors is unstable, and the situation of error sensing happens occasionally. In addition, because pressure sensor need install on the contact, need to have a power failure rear to the equipment in service and can reform transform, the transformation cost is higher, and can only adopt the battery power supply at the high-pressure end, has brought very big difficulty for long-term maintenance.

3) Angle method

The disconnecting switch is usually switched on and off by rotating the contact arm, so that an angle sensor can be additionally arranged on a rotating shaft of the contact arm, and the switching-on and switching-off state of the disconnecting link is monitored through the change of the angle of the contact arm. Compared with a pressure method, under an ideal condition, the angle method can not only effectively reflect the closing condition, but also sense whether the opening is in place.

However, the actual opening and closing positions of the disconnecting switches are not necessarily strictly in the 0 ° and 90 ° orientations due to the precision of machining. Even for the same model of equipment, there are still differences between different batches and different individuals. Moreover, under the condition of outdoor long-term operation, the mechanical position accuracy of the disconnecting link is gradually reduced, and certain dispersion exists for the same disconnecting link in different operations, so that great difficulty is brought to judgment of the angle sensor, and particularly, misjudgment is possible for judgment of switching-on reliability. In addition, due to the limitation of the installation position, the angle sensor also has the problems of high installation and maintenance cost, difficult power supply and the like.

The on-off state perception of the isolating switch essentially solves two basic problems: 1) whether the switch is in place can be effectively judged, and heating of the disconnecting link caused by poor contact of the contact in the operation process is avoided; 2) whether the opening is in place can be effectively judged, and the phenomenon that the air gap of the isolating switch is broken down due to the fact that the insulation distance is not enough after opening is avoided.

In addition, because the number of active isolating switch devices is huge, the realization of state monitoring can only be accomplished by reforming the existing devices in consideration of cost reasons. For safety and cost, the process should be completed under the condition of no power failure as much as possible, and the normal operation of the original equipment should not be influenced. In addition, the additionally installed equipment ensures higher reliability and continuous energy supply, and reduces the operation and maintenance cost.

In summary, in the existing monitoring methods at the present stage, the auxiliary contact method can only indirectly determine the opening and closing conditions of the disconnecting link through the opening and closing of the auxiliary contact, and the determination result is unreliable; the pressure method can only judge whether the switch-on is in place, but cannot judge the in-place situation of the switch-off; the angle method is difficult to adjust due to the dispersion of the mechanical structure, and has a possibility of misjudgment. In addition, the last two methods cannot complete transformation under the condition of no power failure due to the limitation of the installation position, and can only supply power through a battery, so that the requirement of long-term stable operation cannot be met.

Due to the problems, the existing transformer substation site does not have the capability of accurately and effectively carrying out automatic remote sensing on the state of the disconnecting link.

Disclosure of Invention

The invention aims to provide a state sensing method of an open type isolating switch, which can simply, effectively and reliably monitor the state of the open type isolating switch.

In order to achieve the purpose, the invention adopts the technical scheme that:

a state sensing method of an open type isolating switch is used for identifying the on-off state of the open type isolating switch, and comprises the following steps: and shooting a depth image of the open type isolating switch, and identifying the opening and closing state of the open type isolating switch based on the depth image to obtain an identification result.

Preferably, the depth image of the open disconnector is taken by means of infrared light.

Preferably, a depth image of the knife-switch cut of the open-type disconnecting switch is shot.

Preferably, whether the open-type disconnecting switch is switched on in place is identified according to an angle formed between two contact arms of the open-type disconnecting switch or a gap between contacts of the open-type disconnecting switch, wherein the angle is represented in the depth image; and the processing unit identifies whether the open-type isolating switch is in place or not according to the insulation distance between the two contacts of the open-type isolating switch and the included angle of the contact arm of the open-type isolating switch relative to the switching-on position, which are shown in the depth image.

Preferably, a depth image of the open-type disconnecting switch is shot by a depth camera.

Preferably, the processing unit is used for identifying the opening and closing state of the open-type isolating switch based on the depth image.

Preferably, the recognition result and the corresponding depth image are uploaded.

Preferably, machine learning is performed based on the recognition result and applied to recognition of the on/off state of the open-type disconnecting switch.

Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages: the invention can monitor the open-close state of the open-type isolating switch, and has the advantages of easy implementation, effectiveness, reliability, wide application range and the like.

Drawings

FIG. 1 is a schematic diagram of a circuit breaker spacing

Fig. 2 is a flow chart of the programmed switching operation of the circuit breaker.

Fig. 3 is a measurement schematic of a depth image.

Fig. 4 is a schematic view of a depth image.

Fig. 5 is a schematic diagram of a 110kV open-type isolating switch.

Fig. 6 is a depth image of the open-type disconnecting switch when the open-type disconnecting switch is switched on.

FIG. 7 is a depth image of an open-type disconnecting switch when the switch is not in place.

Fig. 8 is a depth image when the open-type disconnecting switch is opened to the position.

Fig. 9 is a depth image of the open-type disconnecting switch when the opening is not in place.

Detailed Description

The invention will be further described with reference to examples of embodiments shown in the drawings to which the invention is attached.

The first embodiment is as follows: the most effective judgment method for the on-off condition of the disconnecting switch is to judge by visually observing the position of a contact, which is also the most widely accepted judgment method generally adopted in the field at present. However, in remote condition monitoring, it is obvious that human eye visualization can no longer be relied upon as a criterion. In recent years, with the continuous development of artificial intelligence, computer vision can replace human eye recognition in many aspects, and in the application scenario, an optical camera can be additionally arranged at a proper position of the disconnecting link, and the effective perception of the position of the disconnecting link can be realized by combining an image recognition technology.

The two-dimensional visible light image is generally used for image recognition at present, and the two-dimensional visible light image has the advantages that the shape and the color of a measured object can be well restored, but the two-dimensional visible light image is insensitive to the spatial position relationship among the objects, so that the algorithm complexity in subsequent image processing is higher. For the position detection of the disconnecting switch, the change of the relative position of the disconnecting switch contact is mainly concerned, and the device needs to monitor the displacement condition of the disconnecting switch in real time, so that the algorithm of image processing is required to be simple to ensure the real-time performance of a calculation result, and therefore the applicability of the two-dimensional visible light image identification technology in the scene is not high.

Based on the method, a novel state sensing method for the open type isolating switch for identifying the on-off state of the open type isolating switch is designed, and the method comprises the following steps: and shooting a depth image of the open type isolating switch, and identifying the opening and closing state of the open type isolating switch based on the depth image to obtain an identification result. The depth image of the open-type isolating switch can be shot by adopting a depth camera, and the opening and closing state of the open-type isolating switch is identified by utilizing the processing unit based on the depth image. Furthermore, machine learning can be carried out based on the identification result, and the machine learning method can be applied to identifying the on-off state of the open type isolating switch.

The depth image uses the parallax principle, so two lenses are needed, for a certain point on a viewed object, the two lenses respectively have the visual angles of α and β, and the distance d between the point and a visual plane can be calculated as follows:

the distances between all points on the object to be viewed and the viewing plane can be obtained, and the depth image shown in fig. 4 can be obtained. Different colors are used in the depth image to represent the distance between the point and the view plane. It can be seen from the figure that the depth image omits the secondary attributes such as the color of the object itself, but completely retains the cross-sectional coordinates and the longitudinal depth of the viewed object, so that the position information of the viewed object can be reflected concisely, and the complexity of the algorithm for identifying the position of the object based on the depth image is greatly reduced.

Furthermore, depth cameras typically construct a depth image by means of infrared light, since there is no need to acquire the true appearance of the viewed object. Since all objects above absolute zero spontaneously radiate infrared rays outward, a depth image of an object to be viewed can be obtained even in a dark environment.

For the application scene of the state perception of the disconnecting switch, the depth camera is installed at a proper position, and the real-time monitoring of the position of the disconnecting switch can be realized. The method of using the typical isolating switch is described as an example. Fig. 5 shows a conventional 110kV open disconnector, which is of a mid-open configuration, with two contacts on two separate bushing legs and a break in the middle. The figure shows the switching-on position of the disconnecting link, and the two contacts respectively rotate to the same side to form an obvious fracture when the disconnecting link is switched off. For the disconnecting link, the depth camera 11 can be installed on the base right below the fracture, so that the lens is aligned with the disconnecting link fracture, that is, the depth camera 11 is arranged corresponding to the disconnecting link fracture of the open-type disconnecting switch, and thus a depth image of the disconnecting link fracture is shot.

When the knife switch contact is in different states, different depth images can be generated on the camera, as shown in fig. 6 to 9. It can be seen that the positions of the contacts of the disconnector in different states show a significant difference. Therefore, in the processing unit, when judging and identifying whether the open type disconnecting switch is switched on in place, the judgment can be carried out according to an angle formed between two contact arms of the open type disconnecting switch or a gap between contacts of the open type disconnecting switch and the like shown in the depth image; when judging and identifying whether the open-type disconnecting switch is in place or not, the judgment can be carried out according to the insulation distance between the two contacts of the open-type disconnecting switch, the included angle between the contact arm of the open-type disconnecting switch and the switching-on position and the like shown in the depth image.

For the open-type disconnecting switch, because a sufficient insulation distance needs to be kept, a certain space distance exists between the conducting rod and other equipment, so that the other equipment in the station is used as a background and is represented as a single color block on a depth image, and the boundary with the open-type disconnecting switch is obvious. Therefore, the device can be used for easily extracting the outline of the object to be observed from the image and finding out the key point needed to be used for judging, thereby realizing the perception of the state of the isolating switch.

Fig. 6 to 9 show depth images of the mid-open disconnector. In fact, for almost all forms of open-type disconnecting switch structures, such as telescopic type, double-port type, single-arm rotary type and the like, as long as the installation position is proper, a depth image with obvious separation of foreground and background and easily distinguished different states can be obtained. Therefore, the device has strong universality for state perception of the isolating switch.

On the basis of the scheme, the identification result and the corresponding depth image can be uploaded, and the uploaded identification result and the corresponding depth image can be used for manual judgment in some suspicious states.

The invention has the beneficial effects that:

(1) the reliability is high. The reliability of the state sensing of the isolating switch can greatly influence the stability of the one-key sequence control system, and misoperation accidents are prevented. In the traditional state perception method, an auxiliary contact method and an angle method are easily influenced by mechanical structure aging, and the reliability degree is low; the pressure method can only detect closing and cannot judge the opening condition. The perception method based on the depth image recognition can effectively separate the contact of the disconnecting link from the background image, has high recognition degree for the form difference of the contact under different states, and is independent of the mechanical structure of the disconnecting link, so the perception method is not influenced by the aging of the structure of the disconnecting link body. In addition, the method can directly provide the depth image besides the automatic identification system, and provides an iconography basis for manual identification.

(2) Has wide application range. In the existing sensing method, the pressure method is only suitable for a disconnecting link with a pressure spring at the contact position, and the angle method is only suitable for a rotary isolating switch. The sensing method provided by the invention is independent of the mechanical structure of the disconnecting link, so that the sensing method can be applied to any form of open-type disconnecting switch by selecting a proper installation position and using a certain machine learning process. In addition, the depth image generally senses the object to be viewed by using an infrared band, and is not influenced by ambient light, so that the depth image is an all-weather and all-form state sensing method.

(3) The improvement cost is low: at present, the existing isolating switches in the power grid are large in quantity, and do not have other state sensing conditions except for auxiliary contacts, so that modification is needed. The sensors required by the pressure method and the angle method are required to be arranged on the high-voltage part of the isolating switch, so that power failure modification is required, and the modification cost is high. The equipment required by the sensing method provided by the invention is not in electric contact with the high-voltage part of the isolating switch, and the equipment can be modified in a charged state. In addition, after data given by the depth camera is processed into a displacement signal by the distributed processing unit, the displacement signal can be directly accessed to the existing monitoring network of the transformer substation, a communication line does not need to be additionally laid, and the normal operation of the existing equipment is not influenced, so the transformation cost of the method is low.

(4) The operation and maintenance are simple. Since the state-aware devices need to be operated in the field for a long period of time, the operation and maintenance costs thereof are a concern. Because the sensors of the pressure method and the angle method are both arranged at the high-voltage part of the equipment, the power can be supplied only by a battery, the power needs to be periodically cut off and replaced, the detection result is easily influenced by the aging of the mechanical structure of the equipment, and the operation and maintenance cost is very high. In the invention, the depth camera is usually installed in a low-voltage area, so that the power can be directly taken nearby from an operation power supply or other positions of the isolating switch without regular replacement, the detection reliability is not influenced by the aging of a mechanical structure of the equipment, and the operation and maintenance cost can be greatly reduced.

The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A state sensing method of an open type isolating switch is used for identifying the on-off state of the open type isolating switch and is characterized in that: the state sensing method of the open-type isolating switch comprises the following steps: and shooting a depth image of the open type isolating switch, and identifying the opening and closing state of the open type isolating switch based on the depth image to obtain an identification result.

2. The method for sensing the state of an open-type disconnector according to claim 1, characterized in that: and shooting a depth image of the open type isolating switch by means of infrared light.

3. The method for sensing the state of an open-type disconnector according to claim 1, characterized in that: and shooting a depth image at the disconnecting link fracture of the open type disconnecting switch.

4. The method for sensing the state of an open-type disconnector according to claim 1, characterized in that: identifying whether the open type disconnecting switch is switched on in place or not according to an angle formed between two contact arms of the open type disconnecting switch or a gap between contacts of the open type disconnecting switch, wherein the angle is represented in the depth image; and the processing unit identifies whether the open-type isolating switch is in place or not according to the insulation distance between the two contacts of the open-type isolating switch and the included angle of the contact arm of the open-type isolating switch relative to the switching-on position, which are shown in the depth image.

5. The method for sensing the state of an open-type disconnector according to claim 1, characterized in that: and shooting a depth image of the open type isolating switch by using a depth camera.

6. The method for sensing the state of an open-type disconnector according to claim 1, characterized in that: and identifying the opening and closing state of the open type isolating switch based on the depth image by using a processing unit.

7. The method for sensing the state of an open-type disconnector according to claim 1, characterized in that: and uploading the recognition result and the corresponding depth image.

8. The method for sensing the state of an open-type disconnector according to claim 1, characterized in that: and performing machine learning based on the identification result and applying the machine learning to identify the on-off state of the open type isolating switch.