CN112665647A - ZigBee-based power grid transformer remote online monitoring system - Google Patents

ZigBee-based power grid transformer remote online monitoring system Download PDF

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CN112665647A
CN112665647A CN202011481088.5A CN202011481088A CN112665647A CN 112665647 A CN112665647 A CN 112665647A CN 202011481088 A CN202011481088 A CN 202011481088A CN 112665647 A CN112665647 A CN 112665647A
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monitoring
transformer
data
zigbee
upper computer
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陈茹
胡绍林
王世华
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Xian University of Technology
Guangdong University of Petrochemical Technology
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Xian University of Technology
Guangdong University of Petrochemical Technology
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Abstract

The invention provides a ZigBee-based power grid transformer remote online monitoring system, which comprises a data acquisition part, a wireless data transmission part and an upper computer monitoring part, wherein the data acquisition part is used for acquiring data; the data acquisition part is used for acquiring data of each state information of the corresponding transformer; the wireless data transmission part is transmitted to the main node through the routing node in the wireless network, and the main node converges the data and finally sends the data to the upper computer monitoring part through the serial port; the upper computer monitoring part receives each group of state data uploaded by the main node through the serial port and displays the state data on an upper computer monitoring interface. The system monitors parameters such as the temperature of a transformer winding, partial discharge, high-voltage bushing current, dissolved gas in oil and the like in real time, can predict possible faults of equipment in time according to the data monitored in real time, prevents the faults from happening in the bud, and reduces various losses caused by the faults of the equipment.

Description

ZigBee-based power grid transformer remote online monitoring system
Technical Field
The invention relates to a remote online monitoring system for a power grid transformer, in particular to a ZigBee-based remote online monitoring system for the power grid transformer.
Background
The transformer is one of important equipment of a power system, and the transformer cannot be used in all links of power transmission, power supply and the like. Generally, transformers are installed in the field and are scattered, once problems occur, the problems are difficult to find and maintain in time, which causes economic loss to a certain extent,
in the early stage of China, a mode of 'regular maintenance' of a transformer is adopted in a power system, whether various operation indexes of the transformer are normal or not is judged through regular preventive tests, and potential faults of a transformer are predicted according to the transformation trend of the indexes, so that the fault rate of the transformer is reduced. On one hand, the establishment of the maintenance period is too rigid, no matter whether the running state of the transformer is good or bad, the transformer is maintained in the preset maintenance period, so that partial good state is inevitably caused, the transformer which does not need to be maintained is also maintained, and the waste of various resources is easily caused. More seriously, the overhaul prolongs the time of the interior of the transformer exposed to the air, greatly increases the possibility that moisture and dust in the air enter the transformer, and may cause new hidden troubles, so that the transformer does not rise or fall at the insulation level after the overhaul, and the aim of regular overhaul is violated. On the other hand, the regular maintenance is carried out in an offline power failure state, and the insulation performance and the working condition of the transformer in field work cannot be accurately represented.
Disclosure of Invention
The purpose of the invention is: the method has the advantages that a complete ZigBee-based power grid transformer remote online monitoring system is established, real-time updated data of the transformer can be collected, data communication between the transformer and a diagnosis evaluation platform is achieved, and simple operation state evaluation is completed.
The technical scheme of the invention is as follows:
ZigBee-based power grid transformer remote online monitoring system comprises: a data acquisition section;
a wireless data transmission section; and an upper computer monitoring part;
the data acquisition part comprises a plurality of groups of monitoring units arranged in a monitoring area of the transformer substation and is used for acquiring data of each state information of the corresponding transformer; each group of monitoring units comprises a partial discharge signal monitoring unit, a gas content proportion monitoring unit, a high-voltage bushing monitoring unit and a winding temperature monitoring unit according to the type of the state information;
the wireless data transmission part is based on networking of a ZigBee technology and comprises a main node, routing nodes and terminal nodes which are in one-to-one correspondence with the multiple groups of monitoring units; the terminal node is connected with a corresponding group of monitoring units through a circuit to obtain the group of state data, the state data are transmitted to the main node through the routing node in the wireless network, and the state data are converged by the main node and finally transmitted to the monitoring part of the upper computer through a serial port;
and the upper computer monitoring part receives each group of state data uploaded by the main node through a serial port and displays the state data on an upper computer monitoring interface.
Preferably, the partial discharge signal monitoring unit adopts an ultrasonic sensor and is fixed on the wall of the transformer oil tank; the passband of the ultrasonic sensor is 70-150 kHZ.
Preferably, the gas content ratio monitoring unit adopts an optical fiber gas sensor, and is installed in an oil way of the transformer through a fixed connecting piece by the oil-gas separator, so that flowing oil directly contacts a probe of the optical fiber gas sensor.
Preferably, the high-voltage bushing monitoring unit adopts voltage and current sensors for obtaining the relative dielectric loss difference value and capacitance ratio of the tested bushing and the reference equipment.
Preferably, the winding temperature monitoring unit adopts a fiber grating temperature sensor and is directly installed on a hot spot of a transformer winding.
Preferably, the terminal node includes a power supply module, a CPU, a memory, an antenna, and a radio frequency transceiver, wherein the CPU is connected to the plurality of monitoring units in the same group through an I/O interface, stores the acquired status data in the memory, and enters the wireless network through the antenna and the radio frequency transceiver.
Preferably, the terminal node employs a chip CC 2530.
Preferably, the host node adopts an embedded chip STC89C51, and realizes data communication with the upper computer monitoring part by using a serial port conversion chip SP 3232.
Preferably, the upper computer monitoring part displays each group of status data uploaded by the main node on an upper computer monitoring interface in a graphical mode based on a GUI of MATLAB.
Preferably, the upper computer monitoring part is further provided with a fault judgment module and an alarm module, and is used for timely and accurately notifying related personnel of fault conditions and storing alarm information in a database.
Compared with the prior art, the invention has the following advantages:
1. the transformer equipment real-time monitoring system adopts a data acquisition part to acquire data obtained by transformer equipment in real time, adopts a wireless data transmission part to transmit the obtained real-time data to an upper computer monitoring part, evaluates the running state of the equipment according to the real-time obtained data, monitors whether the equipment is abnormal in real time, and timely controls and overhauls the equipment if the equipment is abnormal; in addition, possible faults of the equipment can be predicted in time according to the data monitored in real time, the faults are prevented in the bud, and various losses caused by the faults of the equipment are reduced.
2. The invention provides a ZigBee-based power grid transformer remote online monitoring system, which completes the structure construction, sensor type selection, wireless transmission chip type selection and the like of a wireless sensor network. The system has complete functions, can realize real-time monitoring of parameters such as the temperature of a transformer winding, partial discharge, high-voltage bushing current, dissolved gas in oil and the like, and has certain reference value in the field of on-line monitoring of the state of the transformer.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive exercise.
FIG. 1 is a schematic diagram of the general structure of a ZigBee-based remote online monitoring system for a power grid transformer;
FIG. 2 is a schematic view of a partial discharge ultrasonic monitoring system;
FIG. 3 is a schematic view of a gas optical fiber monitoring system in oil;
FIG. 4 is a schematic diagram of a high voltage bushing data collection process;
FIG. 5 is a diagram of a fiber grating thermometry system;
FIG. 6 is a schematic diagram of a winding temperature data acquisition process;
FIG. 7 is a schematic diagram of a CC253 chip connection;
fig. 8 is a flowchart of CC2530 data transmission and reception;
fig. 9 is a transformer monitoring system flow diagram.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
At present, when the abnormity of the power grid is analyzed domestically and abroad, the abnormity is often concentrated on the power grid, and the research on the faults of the power equipment is less. The health condition of the power equipment directly influences whether the power grid can stably operate or not, and particularly, large power transmission and transformation equipment such as a transformer and the like are very important to the operation condition of the power grid.
Fig. 1 is a schematic diagram of the general structure of a ZigBee-based power grid transformer remote online monitoring system, as shown in fig. 1, the technical scheme of the present invention is as follows:
ZigBee-based power grid transformer remote online monitoring system comprises: a data acquisition section; a wireless data transmission section; and an upper computer monitoring part; the data acquisition part comprises a plurality of groups of monitoring units arranged in a monitoring area of the transformer substation and is used for acquiring data of each state information of the corresponding transformer; each group of monitoring units comprises a partial discharge signal monitoring unit, a gas content proportion monitoring unit, a high-voltage bushing monitoring unit and a winding temperature monitoring unit according to the type of the state information; the wireless data transmission part is based on networking of a ZigBee technology and comprises a main node, routing nodes and terminal nodes which are in one-to-one correspondence with the multiple groups of monitoring units; the terminal node is connected with a corresponding group of monitoring units through a circuit to obtain the group of state data, the state data are transmitted to the main node through the routing node in the wireless network, and the state data are converged by the main node and finally transmitted to the monitoring part of the upper computer through a serial port; and the upper computer monitoring part receives each group of state data uploaded by the main node through a serial port and displays the state data on an upper computer monitoring interface.
It should be noted that: the data acquisition part is mainly used for acquiring the state data of the transformer through the nodes. To realize the long-time stable operation of the power transformer, the operation state of the transformer must be monitored in real time. Aiming at the characteristic parameters of various faults possibly generated in the operation process, and considering that the data sources of various technical indexes are easy to obtain technically, the transformer information acquisition system is designed and selected from the following four monitoring parameters:
the first parameter: monitoring partial discharge signals: partial discharge is mainly discharge generated in the internal insulation of a transformer and other high-voltage electrical equipment under the action of high voltage, the partial discharge can generate a large damage effect on the insulation material of the transformer, and the aging and the damage of the internal insulation of the transformer in operation usually start from a partial discharge phenomenon.
The second parameter is: monitoring the gas content proportion: when the transformer is in local overheating or partial discharge, the insulating oil or solid insulator at the fault position can decompose small-molecule hydrocarbon gas (such as CH4, C2H6, C2H4, C2H2 and the like) and other gas (such as H2, CO and the like). The concentration of each gas in the oil and the Total Concentration (TCG) of combustible gas in the oil can be used as indexes for diagnosing the internal fault of the transformer equipment.
The third parameter: monitoring the high-voltage bushing: the bushing is a wire outlet device for leading high-voltage and low-voltage leads inside power equipment (such as a transformer, a reactor and the like) to the outside of an oil tank. The high-voltage bushing insulation performance can be judged by the dielectric loss of the insulator in the bushing, the end screen equivalent capacitance and the end screen leakage current.
The fourth parameter: monitoring the winding temperature: the service life of the power transformer is closely related to the winding temperature rise, and the winding temperature abnormality is usually one of important manifestations of transformer faults, so the transformer winding temperature rise needs to be monitored on line. Whether the temperature rise of a transformer winding exceeds a limit value or not is taken as an important condition for fault judgment when the transformer runs under the condition of rated load or overload.
The wireless data transmission part is mainly used for transmitting transformer data which can be collected by the slave nodes to the master node through a wireless network, then the transformer data are collected by the master node and finally transmitted to an upper computer through a serial port to achieve the purpose of monitoring, and the communication distance can be expanded through the arrangement of the router nodes, so that the coverage range of the wireless sensor network is expanded.
Transformer monitoring facilities erect in the field and need the parameter of research more in the transformer monitoring with the transformer commonly, monitoring facilities need have low energy consumption and considerable extensible network nature then, compare with other wireless communication technologies, Zigbee wireless communication technology Zigbee has following advantage:
(1) low power consumption: under the working mode, the receiving and sending time of the signal is very short, and under the condition of the non-working mode, the node of the ZigBee is in a dormant state, so that the ZigBee node is very power-saving. The battery operating time of a ZigBee node can typically be as long as 6 months to 2 years, and can even exceed ten years. Compared with the Bluetooth which can only work for weeks and the WIFI which can only work for hours, the ZigBee technology has obvious advantages.
(2) The cost is low: by greatly simplifying the protocol, the requirements on the storage and computation capabilities of the nodes are reduced. According to the research, the 8-bit microcontroller of 8051 is used for measurement, the full-function device needs 32K codes, the simplified function only needs 4KB codes, and the ZigBee protocol patent is free.
(3) The network capacity is large: the network nodes of one ZigBee include 255 ZigBee network nodes at most, wherein one ZigBee network node is a Master (Master) device, and the rest ZigBee network nodes are slave (Slove) devices. If the Network Coordinator (Network Coordinator) is used, the whole Network can support more than 64000 ZigBee Network nodes, and in addition, the Network coordinators can be connected with each other, so that the number of the Network nodes of the whole ZigBee Network is considerable.
The GUI upper computer monitoring part based on MATLAB has the functions of receiving data transmitted by a network through a serial port, visually displaying the data through an upper computer monitoring interface in a graphic mode, timely and accurately notifying relevant personnel of a fault condition, and storing alarm information in a database so that the personnel on duty can take corresponding safeguard measures.
In the remote monitoring process of the transformer, a reasonable network communication architecture is required to be built for realizing the data communication between the equipment site and the data processing center, and the information acquisition of the running state of the transformer in the transformer substation can be realized by applying a wireless sensing network technology. The system requires deployment of sensor nodes to enable the sensor nodes to form a wireless sensor network in a transformer substation monitoring area, real-time collection of transformer data in an operating state is completed by terminal nodes, and the collected data is transmitted to a monitoring center through the built wireless sensor network. The wireless sensor network mainly comprises a data acquisition part based on a terminal node and a wireless transmission part based on ZigBee networking.
The transformer data acquisition part based on the sensor terminal nodes mainly utilizes the setting of the terminal nodes to acquire various state information quantities of the transformer through the sensors, wherein the state information quantities comprise various data related to the running state of the transformer such as winding temperature, partial discharge quantity, gas in oil and the like, the acquired data are sent to an upper network [19] in a data frame mode, and the terminal nodes can be configured with different sensors according to different acquired transformer signals so as to realize the acquisition of the multi-state quantity data information of the transformer in running.
The sensors for collecting data all adopt the sensor types selected in the previous section.
The networking and wireless data transmission part based on the ZigBee technology mainly achieves the purposes that transformer data which can be collected by terminal nodes are transmitted to coordinator nodes through a wireless network, then the transformer data are converged by the coordinator nodes and finally transmitted to an upper computer through a serial port to achieve monitoring, and the communication distance can be expanded through the arrangement of the router nodes, so that the coverage range of a wireless sensor network is expanded.
Preferably, the partial discharge signal monitoring unit adopts an ultrasonic sensor and is fixed on the wall of the transformer oil tank; the passband of the ultrasonic sensor is 70-150 kHZ.
Partial discharge monitoring-ultrasonic sensors: the partial discharge refers to a discharge phenomenon generated by the insulation inside a transformer, a mutual inductor and other high-voltage electrical equipment under the action of high voltage. The traditional partial discharge monitoring method is a pulse current method, which is the basis of partial discharge research, but electric pulse signals have great interference during field detection, so that the discharge signals are difficult to obtain correctly, and in addition, the problems of equivalence between online results and offline results and the like exist. The novel ultrasonic sensor perfectly avoids the problems. Firstly, the ultrasonic sensor has strong electromagnetic interference resistance, and the currently adopted ultrasonic partial discharge detection method is to detect on the shell part of the electrical equipment by using the ultrasonic sensor. Because the power equipment has stronger electromagnetic interference in the operation process, and the ultrasonic detection is a non-electric detection method, the detection frequency band can effectively avoid the electromagnetic interference, and a better detection effect is obtained. And secondly, the ultrasonic sensor can realize discharge positioning, and the determination of the partial discharge position can provide effective data reference for the diagnosis of equipment defects and reduce the overhaul time. Meanwhile, the ultrasonic signals have strong directivity and concentrated energy in the transmission process, so that directional and concentrated beams can be easily obtained in the detection process, and the positioning is convenient. The ultrasonic partial discharge detection can be classified into contact detection and non-contact detection according to the propagation path of the ultrasonic signal. Contact ultrasonic detection is mainly used for detecting ultrasonic signals on the surfaces of shells of equipment such as GIS (gas insulated switchgear), transformers and the like, and non-contact ultrasonic detection can be used for detecting equipment such as switch cabinets, distribution lines and the like.
At present, a relatively mature positioning system is available in the market. The piezoelectric ultrasonic sensor is used for monitoring the partial discharge problem, and the sensor has good anti-interference performance and positioning capacity, so that the partial discharge monitoring can be realized, and the discharge position of the partial discharge monitoring can be accurately positioned. An ultrasonic sensor fixed on the wall of a transformer oil tank is generally adopted to receive ultrasonic waves generated by partial discharge inside the transformer so as to detect the size and the position of the partial discharge. The piezoelectric ultrasonic transducer is adopted in engineering, the selected frequency range is 70-150kHz, and the purpose is to avoid magnetic noise of an iron core and mechanical vibration noise of a transformer. The ultrasonic detection method is mainly used for qualitatively judging whether partial discharge signals exist or not and combining electric pulse signals or directly utilizing ultrasonic signals to physically position partial discharge sources.
When partial discharge occurs in the transformer, ultrasonic waves are emitted, so that whether partial discharge occurs or not can be determined according to received signal waveforms and frequency spectrum analysis, and a partial discharge source is positioned. The partial discharge data acquisition system comprises an ultrasonic signal acquisition part, a pre-amplification part, a filtering part, a main-stage amplification part and an A/D conversion part. The frequency spectrum of partial discharge signals of the transformer is wide, the partial discharge signals are distributed on 40kHz-130kHZ generally, the fluctuation is large, and the central frequency of partial discharge signals of ultrahigh voltage large-scale transformation is 148 kHz. The passband of the ultrasonic sensor adopted at this time is 70-150 kHZ. The partial discharge ultrasonic positioning system is a weak signal detection system under strong background noise, as shown in fig. 2, so a high-sensitivity low-noise amplification and filtering module must be added. The coupling transformer is matched with the input stage of the preamplifier, the preamplifier is directly combined in the sensor, the photoelectric conversion equipment is added between the preamplifier and the main amplification filter by adopting a method of optical fiber analog transmission electric signals, and the optical fiber is used for transmitting partial discharge signals, so that the optical fiber sensor can transmit any distance theoretically. The front-end amplifier adopts a two-stage filter structure to further amplify the front-end amplifier signal at the front-end of the main amplifier, the data acquisition subsystem mainly completes the A/D conversion of the partial discharge sound signal, and simultaneously provides a D/A output port, so that the partial discharge signal stored after the A/D conversion can be observed in real time by using an oscilloscope, and the aim of dynamic monitoring is fulfilled.
Preferably, the gas content ratio monitoring unit adopts an optical fiber gas sensor, and is installed in an oil way of the transformer through a fixed connecting piece by the oil-gas separator, so that flowing oil directly contacts a probe of the optical fiber gas sensor.
Gas in oil monitoring-fiber gas sensor: when the transformer is in local overheating or partial discharge, the insulating oil or solid insulator at the fault position can decompose small-molecule hydrocarbon gas (such as CH4, C2H6, C2H4, C2H2 and the like) and other gas (such as H2, CO and the like). The concentration of each gas in oil and the Total Concentration (TCG) of combustible gas in oil can be used as indexes for diagnosing internal faults of transformer equipment, the internal faults of the transformer are different, and the generated gas is the same or different. The main gases considered to be of particular interest for determining transformer faults are: h2, CO2, CH4, C2H6, C2H4, C2H2, O2, N2, and the like. Through the analysis, the fault state, degree, damage and other conditions in the transformer can be analyzed and diagnosed according to the composition, content and gas production rate of gas release caused by the fault state, degree, damage and other conditions.
The optical fiber gas sensor is adopted for monitoring the gas in the transformer oil, and the light intensity attenuation generated by gas absorption is measured by utilizing the absorption peak of the gas in the quartz optical fiber transmission window, so that the concentration of the gas can be obtained. By calibrating the position of the absorption peak, the type of the gas can be further identified. The gas component characteristics are different along with the difference of fault types, fault energy and related insulating materials, when data information of dissolved gas in oil is collected, firstly, an oil-gas separator is arranged at a position where equipment oil flows well through a connecting piece (in a flange or thread form), the flowing oil directly contacts a permeable membrane, the fault characteristic gas dissolved in the oil enters a gas chamber to act on an optical fiber gas sensor after oil-gas separation is realized through the permeable membrane, the gas sensor converts a gas concentration value in the gas chamber into an electric signal, and the electric signal is amplified and transmitted to a main module to obtain a data signal. The process is shown in figure 3.
Preferably, the high-voltage bushing monitoring unit adopts voltage and current sensors for obtaining the relative dielectric loss difference value and capacitance ratio of the tested bushing and the reference equipment.
High-voltage bushing leakage monitoring-voltage current sensor: the transformer high-voltage bushing usually adopts an insulation structure in a capacitance voltage-sharing mode, the dielectric loss tan delta and the capacitance are the most direct and effective parameters for measuring the insulation performance of the transformer high-voltage bushing, and the accurate monitoring of the dielectric loss and the capacitance of the transformer high-voltage bushing in the operation process of equipment is particularly important. Firstly, an original current signal is obtained by a current sensor from a high-voltage bushing end screen grounding wire and is converted into a voltage signal, meanwhile, a reference voltage signal is obtained from a secondary terminal box of a voltage transformer (PT), after the two voltage signals are filtered, amplified and shaped, the phase difference of fundamental wave components of the two current signals is accurately obtained by a pure mathematical method of fast Fourier transform into a core through harmonic analysis, and therefore the relative dielectric loss difference value and the capacitance ratio of a tested bushing and reference equipment are obtained. The process is shown in fig. 4.
Preferably, the winding temperature monitoring unit adopts a fiber grating temperature sensor and is directly installed on a hot spot of a transformer winding.
Winding temperature sensor-grating fiber temperature sensor: the inside of the transformer is an environment with a high-voltage strong magnetic field, if a traditional temperature sensor is adopted to transmit an electric signal through a metal wire to realize measurement, the potential difference between the sensor wire and a winding in an oil tank can cause the insulation oil of the transformer to break down. At present, in the monitoring of the transformer winding temperature, a direct measurement method is mainly adopted in engineering, a temperature measurement sensor probe is implanted near a winding, so that the temperature distribution condition of the winding can be accurately obtained, theoretically, the result of the temperature measurement method is accurate, but the sensor probe implanted in the transformer winding can damage the structure of the transformer winding, influence the insulativity and further influence the normal operation of the transformer in consideration of the sealing property inside the transformer, and therefore the direct temperature measurement method has high requirements on the structural design of the sensor and the transformer. Usually, a winding thermometer is also adopted to monitor the temperature of the transformer winding, a current matcher and an electric heating element are arranged on the basis of an oil temperature meter, and the temperature of the transformer winding is reflected by temperature superposition. The temperature measuring method is simple, but has large error. The introduction of optical fiber technology provides a good way to measure the temperature of the transformer winding. An optical fiber sensor is directly buried in a transformer winding, when the temperature of the sensor changes, some physical parameters of light can change along with the temperature change, so that the light can be modulated to obtain the temperature distribution condition around a temperature measuring probe, the light can be modulated in various ways such as wavelength modulation, amplitude modulation, frequency and phase modulation, and different temperature measuring sensors based on optical fibers can be generated according to different modulation methods. However, each modulation method has advantages and disadvantages, and thus, application fields thereof are greatly different.
The most excellent performance of the fiber grating temperature sensor in many types of fiber sensors is shown in fig. 5, and since the temperature sensing device of the temperature sensor is a grating, the central wavelength of the reflected light changes when the measured temperature, stress and the like of the outside change. The fiber grating sensor has very good reliability and stability because the fiber grating encodes the sensed information by using wavelength, and the wavelength is an absolute parameter and is not influenced by system loss caused by factors such as light source power fluctuation and fiber bending. The optical fiber is arranged on a winding hot spot and is influenced by temperature, the reflection wavelength of the optical fiber grating moves, and the movement of the wavelength and the temperature change form a linear relation, so that the temperature of the measuring point can be obtained. The grating is written into the optical fiber by the ultraviolet technology, so the sensor probe is actually the optical fiber and is very easy to install. Generally speaking, fiber grating temperature sensor compares in other types of sensor, the advantage is obvious, owing to need not supply power at the scene, so the measurement of temperature can not be influenced to strong electromagnetic interference around the transformer, measured resolution ratio and precision are high, response speed is very fast, can long-time placing in the temperature measurement environment that corrosivity is strong, high humidity, high temperature, line loss and light source decay also can not cause the influence, the sensor also can realize distributed arrangement, realize the multiple spot and measure, can the adaptation transformer dispersion in the control demand in the field.
The grating temperature measurement controls the piezoelectric body on the filter to repeatedly scan the free spectral range through the sawtooth wave, when the wavelength of the filter is coincided with the central wavelength of the fiber grating sensor, the light reflected from the fiber grating sensor is detected in the photoelectric detector, the voltage value in the photoelectric detector is collected by the data acquisition card, an external input signal is converted into a voltage signal through the temperature sensor, the voltage signal is adjusted to be in a standard signal range through the signal conditioning circuit, and then the voltage signal is converted into a digital signal through the A/D conversion circuit, as shown in figure 6.
Preferably, the terminal node includes a power supply module, a CPU, a memory, an antenna, and a radio frequency transceiver, wherein the CPU is connected to the plurality of monitoring units in the same group through an I/O interface, stores the acquired status data in the memory, and enters the wireless network through the antenna and the radio frequency transceiver.
Preferably, the terminal node employs a chip CC 2530.
Preferably, the host node adopts an embedded chip STC89C51, and realizes data communication with the upper computer monitoring part by using a serial port conversion chip SP 3232.
The ZigBee chip adopts CC2530, can realize through this chip and peripheral circuit and link to each other with the terminal node, realize the connection with the sensor promptly, link to each other through the circuit with the terminal node of ZigBee directly with sensor one end, the other end embedding is installed in the box of transformer or is connected with the transformer box of corresponding monitoring position. Different types of sensors, such as temperature, gas sensors, etc., are configured for different applications depending on the needs of the actual sensing. The network coordinator adopts an embedded technology and a Zigbee communication module, the coordinator node receives and stores transformer data information sent by the terminal node, simple data processing is carried out through a microprocessor of an embedded chip STC89C51, and then data communication with a PC (personal computer) is realized by utilizing a serial port conversion chip SP3232, so that interconnection between a wireless sensor network and the PC (monitoring center) is realized. The chip connection diagram is shown in fig. 7, and the data transmission and reception process is shown in fig. 8.
Preferably, the upper computer monitoring part displays each group of status data uploaded by the main node on an upper computer monitoring interface in a graphical mode based on a GUI of MATLAB.
The MATLAB is adopted to design a user real-time monitoring system, the development environment of the MATLAB is provided with a drag-and-drop user interface library, and a user can conveniently and quickly design a very professional interface through dragging and dropping controls in a control configuration board. It has thousands of built-in functions, and can conveniently and quickly create application programs by drag-and-drop through a function configuration board. The built-in acquisition, analysis and display tool enables the device to be easily connected with any measurement hardware, and through more than 500 built-in functions, effective information can be extracted from acquired data without considering a complex underlying algorithm, measurement results can be analyzed and signals can be processed, and data can be visually displayed through the visual display tool.
The design of the monitoring interface adopts a modularized design idea, MATLAB software is applied to design each sub-interface respectively, corresponding programs are created and generated, and finally the sub-programs of the modules are connected to complete the design of the whole monitoring interface, wherein the design of the monitoring interface mainly comprises the following steps: the design of a login interface, the design of a starting interface, the design of a main interface and the design and programming of a transformer monitoring function interface. Because the communication between the data and the upper computer is displayed through the GUI, the serial port communication program of the monitoring system is also written by MATLAB. The transformer monitoring system flow is shown in fig. 9.
Preferably, the upper computer monitoring part is further provided with a fault judgment module and an alarm module, and is used for timely and accurately notifying related personnel of fault conditions and storing alarm information in a database. It should be noted that: the power grid fault detection method has the advantages that the power grid fault detection method can timely find and maintain the power equipment before the power equipment fault occurs, the reliability of the operation equipment is improved, and the operation performance of the operation of a power grid can be improved. The running state of the equipment can directly reflect the health condition of the equipment, and if the equipment is abnormal, the corresponding running parameters are obviously different from those in normal running. The continuously developed state monitoring technology provides possibility for mastering the running state of the electrical equipment, so that the defect of insufficient or excessive maintenance in the traditional maintenance mode can be overcome, and the reliability of the equipment is improved. Therefore, the running state of the equipment is evaluated according to the data obtained by monitoring the state of the equipment, the vigilance is improved when the monitored data is abnormal, the equipment is analyzed, the possible fault of the equipment is predicted, the equipment is controlled or overhauled, the trouble is prevented, and the loss caused by the fault of the equipment is reduced.
To sum up, the transformer monitoring system functions include: the transformer running state data real-time display function, the data real-time storage function, the abnormal state alarm function and the historical data query function. The system can realize the monitoring function (such as temperature monitoring, partial discharge monitoring and the like) of each parameter data. The change trend of the parameters is displayed in real time, the received data information is dynamically displayed in a coordinate graph of a monitoring platform, the update change of the real-time waveform can be seen, warning and alarming are carried out when the data are abnormal, the conditions that the temperature is too high or the content of combustible gas changes and the like can be prompted to work personnel, and the personnel can design a targeted maintenance scheme by combining the alarming condition. Meanwhile, the platform can store data in real time and can call historical monitoring data for comparison, so that workers can conveniently arrange maintenance according to needs.
Transformer failures often cause power system outages, resulting in significant economic losses and social impact. The invention provides a transformer state monitoring system based on a ZigBee wireless communication technology, which completes the structure construction of a wireless sensor network, the sensor type selection, the wireless transmission chip type selection and the like. The system has complete functions, can realize real-time monitoring of parameters such as the temperature of a transformer winding, partial discharge, high-voltage bushing current, dissolved gas in oil and the like, and has certain reference value in the field of on-line monitoring of the state of the transformer.
Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Claims (10)

1. ZigBee-based power grid transformer remote online monitoring system is characterized by comprising:
a data acquisition section;
a wireless data transmission section;
and an upper computer monitoring part;
the data acquisition part comprises a plurality of groups of monitoring units arranged in a monitoring area of the transformer substation and is used for acquiring data of each state information of the corresponding transformer; each group of monitoring units comprises a partial discharge signal monitoring unit, a gas content proportion monitoring unit, a high-voltage bushing monitoring unit and a winding temperature monitoring unit according to the type of the state information;
the wireless data transmission part is based on networking of a ZigBee technology and comprises a main node, routing nodes and terminal nodes which are in one-to-one correspondence with the multiple groups of monitoring units; the terminal node is connected with a corresponding group of monitoring units through a circuit to obtain the group of state data, the state data are transmitted to the main node through the routing node in the wireless network, and the state data are converged by the main node and finally transmitted to the monitoring part of the upper computer through a serial port;
and the upper computer monitoring part receives each group of state data uploaded by the main node through a serial port and displays the state data on an upper computer monitoring interface.
2. The ZigBee-based power grid transformer remote online monitoring system of claim 1, wherein: the partial discharge signal monitoring unit adopts an ultrasonic sensor and is fixed on the wall of the transformer oil tank; the passband of the ultrasonic sensor is 70-150 kHZ.
3. The ZigBee-based power grid transformer remote online monitoring system of claim 1, wherein: the gas content proportion monitoring unit adopts an optical fiber gas sensor, and is arranged in an oil way of the transformer through a fixed connecting piece by an oil-gas separator, so that flowing oil directly contacts a probe of the optical fiber gas sensor.
4. The ZigBee-based power grid transformer remote online monitoring system of claim 1, wherein: and the high-voltage bushing monitoring unit adopts voltage and current sensors and is used for obtaining the relative dielectric loss difference value and the capacitance ratio of the tested bushing and the reference equipment.
5. The ZigBee-based power grid transformer remote online monitoring system of claim 1, wherein: the winding temperature monitoring unit adopts a fiber bragg grating temperature sensor and is directly installed on a hot spot of a transformer winding.
6. The ZigBee-based power grid transformer remote online monitoring system of claim 1, wherein: the terminal node comprises a power supply module, a CPU, a memory, an antenna and a radio frequency transceiver, wherein the CPU is connected with multiple monitoring units in the same group through an I/O interface, stores the acquired state data into the memory and enters the wireless network through the antenna and the radio frequency transceiver.
7. The ZigBee-based power grid transformer remote online monitoring system of claim 6, wherein: the terminal node employs a chip CC 2530.
8. The ZigBee-based power grid transformer remote online monitoring system of claim 6, wherein: the host node adopts an embedded chip STC89C51, and realizes data communication with an upper computer monitoring part by using a serial port conversion chip SP 3232.
9. The ZigBee-based power grid transformer remote online monitoring system of claim 1, wherein: and the upper computer monitoring part displays each group of state data uploaded by the main node on an upper computer monitoring interface in a graphical mode based on the GUI of the MATLAB.
10. The ZigBee-based power grid transformer remote online monitoring system of claim 9, wherein: the upper computer monitoring part is also provided with a fault judgment module and an alarm module, and is used for timely and accurately notifying related personnel of fault conditions and simultaneously storing alarm information in a database.
CN202011481088.5A 2020-12-15 2020-12-15 ZigBee-based power grid transformer remote online monitoring system Withdrawn CN112665647A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114325155A (en) * 2021-11-19 2022-04-12 国网湖南省电力有限公司 Fault detection system for transformer
CN114441996A (en) * 2022-01-27 2022-05-06 黄淮学院 Internet of things equipment fault diagnosis method based on artificial intelligence
CN116337782A (en) * 2023-02-28 2023-06-27 重庆大学 Method and system for simultaneously detecting dissolved gas and partial discharge in insulating oil

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114325155A (en) * 2021-11-19 2022-04-12 国网湖南省电力有限公司 Fault detection system for transformer
CN114441996A (en) * 2022-01-27 2022-05-06 黄淮学院 Internet of things equipment fault diagnosis method based on artificial intelligence
CN116337782A (en) * 2023-02-28 2023-06-27 重庆大学 Method and system for simultaneously detecting dissolved gas and partial discharge in insulating oil
CN116337782B (en) * 2023-02-28 2024-03-12 重庆大学 Method and system for simultaneously detecting dissolved gas and partial discharge in insulating oil

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