CN112803597A - Circuit breaker, low-voltage distribution network system and fault monitoring method - Google Patents
Circuit breaker, low-voltage distribution network system and fault monitoring method Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
- H02J13/00002—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by monitoring
Abstract
The invention relates to a circuit breaker, a low-voltage distribution network system and a fault monitoring method. A circuit breaker comprises a low-current topological signal injection module, a low-current topological signal identification module, a fault study and judgment positioning module, an electric energy metering module, a detection module, a communication module and a processing module; the low-current topological signal injection module is used for injecting a low-current topological signal into the power distribution network according to the instruction of the processing module; the low-current topological signal identification module is used for receiving and identifying a low-current topological signal in the power distribution network and transmitting the low-current topological signal to the processing module. When the circuit breaker provided by the invention is arranged at a corresponding position of a power distribution network system, the low-current topological signal injection module and the low-current topological signal identification module are matched for use, so that the topology identification can be carried out on the premise of not influencing the normal operation of the power distribution network and the working communication frequency, the accuracy and the rapidness of the topology identification are ensured, and meanwhile, the circuit breaker integrates fault monitoring and data metering into a whole, and is convenient and rapid.
Description
Technical Field
The present invention relates to electronic devices, and in particular, to a circuit breaker, a low-voltage distribution network system, and a fault monitoring method.
Background
The low-voltage distribution network is positioned at the tail end of the whole power grid, has the characteristics of wide distribution, complex power supply and utilization environment, high operation and maintenance difficulty and the like, and is lack of intelligent and efficient operation monitoring and operation and maintenance management means for a long time, so that the low-voltage distribution network cannot realize accurate attribution of a transformer area, branches and a user shift case, cannot automatically draw a complete low-voltage topological relation, cannot report power failure and recovery information in real time, and cannot better provide data support for a power supply service command platform.
With the continuous improvement of the requirements of fine distribution areas and lean management of low-voltage distribution networks, new requirements are provided for functions of leakage protection, line loss analysis, fault early warning and judgment, distribution area topology analysis and the like of low-voltage switches, and new technical requirements of the Internet of things such as equipment plug and play, edge computing technology and the like are also provided. The low-voltage circuit breaker plays the effect of protection and energy distribution as key equipment in the low-voltage distribution network, and its current situation and problem are that the function is single, do not possess intelligent monitoring ability, standard are not unified. The method comprises the following specific steps:
the action value and the action time of the thermomagnetic circuit breaker are generally fixed, the thermomagnetic circuit breaker only has two-stage protection functions of heat and magnetism, the protection precision is poor, a three-stage protection mode based on a stage difference matching mode is difficult to realize, the isolation interval is large after a fault occurs, the power failure range is enlarged, and the fault point cannot be accurately positioned. In addition, the influence of temperature is large, capacity reduction operation is needed in high-temperature weather, and misoperation is easily caused. And after the overload fault protection of the line outgoing line, the circuit can be switched on again after long-time cooling, and the power supply can not be recovered quickly.
And the residual current circuit breaker is used for protecting the residual current according to the set fixed value. However, the problem faced at present is that there is a false trip, which causes part of the residual current protector to quit operation! Or fail to operate normally! Including the following factors:
the residual current is generated due to bad operating environment of the low-voltage distribution network, insulation aging of equipment, temporary lap joint, electricity stealing and other bad electricity utilization. The setting of the fixed value is related to the wiring mode of the low-voltage distribution network, the grounding of the shell of the electrical equipment, the environment temperature and humidity and the climate.
In recent years, electronic molded case circuit breakers have defects, and need to improve current sampling precision and monitoring range, expand advanced functional applications such as topology recognition, line loss analysis, human body electric shock and the like. Data cannot be uploaded timely and reliably, and plug and play is not supported. The fault point can not be positioned, the power failure interval can not be monitored, and the personnel need to be transported and inspected to patrol the line to remove the fault. The intelligent circuit breakers are not applied to the market in batches, so that the sensing and monitoring of low-voltage distribution network nodes are still large blind areas, and the operation and maintenance difficulty is increased.
The power grid company provides concepts of 'ubiquitous power internet of things' and 'digital power grid', and the low-voltage switch belongs to end equipment in a 'cloud, pipe, edge and end' four-layer architecture, is a power distribution network sensing node and comprises operation state sensing, equipment health state sensing and environmental condition change sensing. Therefore, the development trend of the low-voltage switch is to realize three remote operations, fault study and judgment and protection, namely protection, measurement, metering, monitoring, fault early warning, fault positioning and isolation, auxiliary line loss analysis, household variable relation, topology identification and other functions, so that the intelligent sensing capability of a data source is improved, and the comprehensive acquisition of low-voltage electrical equipment information and remote data interaction are realized.
For the not enough current situation of solving current circuit breaker and platform district control: the topology is realized by lacking effective technical means, and researchers propose a large-current topology scheme: the controllable silicon is utilized to generate a large current near the zero crossing point of the alternating current commercial power, and the defect that only one pulse waveform can be generated in each 20ms period, and the topology signal injection can be completed only after a plurality of periods are continued for a long time; this scheme utilizes the silicon controlled rectifier to produce instantaneous heavy current with the instantaneous short circuit of live wire and zero line, produces great line loss, if control is improper, can produce huge short-circuit current, has certain potential safety hazard.
The low-voltage transformer area lacks panoramic perception and visual monitoring, the electrical relation of the transformer area is unclear, the power supply line points are many-sided and wide, the path is complex, manual topology identification is difficult to realize, faults can not be accurately positioned, and the repair efficiency is low, and customers complain much.
At present, the intelligent level of circuit breaker equipment is low, the data perception ability is not enough, and in order to realize panorama perception and visual monitoring, various monitoring and communication equipment are additionally arranged on the original complex platform district circuit, are difficult to manage and have potential safety hazards, and still need to be improved and improved.
Disclosure of Invention
In view of the defects of the prior art, the invention aims to provide a circuit breaker, a low-voltage distribution network system and a fault monitoring method, which can perform topology communication by using low current, and simultaneously perform intelligent integration and improve the intelligence of equipment.
In order to achieve the purpose, the invention adopts the following technical scheme:
a circuit breaker comprises a low-current topological signal injection module, a low-current topological signal identification module, a fault study and judgment positioning module, an electric energy metering module, a detection module, a communication module and a processing module;
the low-current topological signal injection module is used for injecting a low-current topological signal into the power distribution network according to the instruction of the processing module;
the small current topological signal identification module is used for receiving and identifying a small current topological signal in the power distribution network and transmitting the small current topological signal to the processing module;
the detection module is used for detecting voltage data and current data of the distribution line;
the fault studying, judging and positioning module is used for identifying fault information according to the voltage data and the current data and sending the fault information to the processing module;
the electric energy metering module is used for identifying fault information according to the voltage data and the current data to form metering data and sending the metering data to the processing module;
the processing module drives the low-current topological signal injection module and the low-current topological signal identification module to normally work, receives the fault information and the metering data, and simultaneously performs information interaction with a server through the communication module.
Preferably, in the circuit breaker, the low-current topological signal injection module includes an injection optocoupler, a full-bridge rectification unit, and a signal generation switch; the full-bridge rectifying unit is connected with the secondary side of the injection optocoupler through the signal generation switch, and meanwhile, the full-bridge rectifying unit is connected into a single-phase loop of a distribution line; and the primary side of the injection optocoupler is connected with the processing module.
Preferably, the detection module of the circuit breaker comprises a plurality of current transformers and a plurality of voltage sensors, and the detection module is respectively connected with the fault studying and judging and positioning module and the electric energy metering module.
Preferably, the fault studying and judging and positioning module comprises a plurality of identical studying and judging units; the judging unit comprises an operational amplifier, the input end of the operational amplifier is connected with the detection module, and the output end of the operational amplifier is connected with the processing module.
Preferably, the electric energy metering module is a metering chip; the model of the metering chip is HT 7132.
Preferably, the communication module of the circuit breaker is a wireless communication device.
A low-voltage distribution network system comprises a fusion terminal and a plurality of circuit breakers; the circuit breakers are respectively arranged at a plurality of key nodes in a distribution network topological structure and are connected to a distribution network;
the fusion terminal is arranged at the node position of the transformer area, is in communication connection with the circuit breaker at the current node position, and is used for acquiring the topological structure of the transformer area and monitoring the faults of the transformer area.
Preferably, in the low-voltage distribution network system, the acquisition step of the platform area topology structure is as follows:
sequentially starting circuit breakers at end node positions to inject a small current topological signal attached with current meter information into the power distribution network;
the breaker which receives the small current topological signal adds the table information and then sends the small current topological signal to the power distribution network again;
and sending the collected circuit breakers at the node positions of the transformer in the transformer area to the fusion terminal to form a topological structure of the power distribution network.
A low-voltage distribution network fault monitoring method suitable for the low-voltage distribution network system comprises the following steps:
the circuit breakers of all key nodes determine fault types according to the acquired voltage data and current data;
and uploading the fault type data, the current data, the voltage data and the parameter data to the fusion terminal.
Preferably, the fault monitoring method for the low-voltage distribution network includes: three phase fault, two phase short circuit, relative neutral fault, relative earth fault.
Compared with the prior art, the circuit breaker, the low-voltage distribution network system and the fault monitoring method provided by the invention have the following beneficial effects:
1. when the breaker is arranged at a corresponding position of a power distribution network system, the low-current topological signal injection module and the low-current topological signal identification module are matched for use, so that the topology identification can be carried out on the premise of not influencing the normal operation of the power distribution network and the working signal frequency, the accuracy and the rapidness of the topology identification are ensured, and meanwhile, the breaker integrates fault monitoring and data metering into a whole, and is convenient and rapid;
2. the low-voltage distribution network provided by the invention solves the problem of fuzzy relation of 'household-transformer' and 'household-box-transformer' of the low-voltage distribution network by adopting a low-current topology injection and identification technology, and realizes that 'transformer, line, box and household' are observable and measurable, thereby improving the power supply service capability.
Drawings
Fig. 1 is a block diagram of a circuit breaker according to the present invention;
FIG. 2 is a circuit diagram of a low current topology signal injection module provided by the present invention;
FIG. 3 is a diagram of a current transformer detection circuit provided by the present invention;
FIG. 4 is a circuit diagram for fault diagnosis provided by the present invention;
FIG. 5 is a circuit diagram of a metrology chip provided by the present invention;
FIG. 6 is a block diagram of the low voltage distribution network system provided by the present invention in a normal state;
FIG. 7 is a block diagram of a low voltage power distribution network system provided by the present invention in a fault configuration;
fig. 8 is a fault state diagram of four fault types for a low voltage distribution substation provided by the present invention.
Detailed Description
In order to make the objects, technical solutions and effects of the present invention clearer and clearer, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
It is to be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of specific embodiments of the invention, and are not intended to limit the invention.
The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps, but may include other steps not expressly listed or inherent to such process or method. Also, without further limitation, one or more devices or subsystems, elements or structures or components beginning with "comprise. The appearances of the phrases "in one embodiment," "in another embodiment," and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
Referring to fig. 1, the present invention provides a circuit breaker, which includes a low current topological signal injection module 1, a low current topological signal identification module 2, a fault study and determination positioning module 3, an electric energy metering module 4, a detection module 5, a communication module 6 and a processing module 7;
the low-current topological signal injection module 1 is used for injecting a low-current topological signal into the power distribution network according to the instruction of the processing module 7; specifically, the low-current topological signal injection module 1 is a low-current injection module commonly used in the field, and adopts low-current injection which hardly affects a power grid. The low-current topological signal injection module 1 is mainly used for injecting a low-current topological signal when a whole power distribution network topological structure is constructed.
The low-current topological signal identification module 2 is used for receiving and identifying a low-current topological signal in the power distribution network and transmitting the low-current topological signal to the processing module 7; specifically, the low-current topological signal identification module 2 is a low-current identification module commonly used in the art, is not specifically limited, and is configured corresponding to the low-current topological signal injection module 1; the method is used for identifying the passing low-current topological signals in the power distribution network when the whole power distribution network topological structure is constructed. Through the matching use of the small-current topological signal injection module 1 and the small-current topological signal identification module 2, namely two functional modules are configured on each key node in the power distribution network, the topology detection and the topology signal injection of the current key position to downstream equipment can be realized, and the identification of a topological structure can be quickly realized on the basis of not influencing a power distribution network. At this time, the identification of the topology structure also requires a corresponding processing center to perform comprehensive processing and analysis of data, and the specific analysis method may use a topology identification method commonly used in the art, which is not specifically limited in this embodiment. The key nodes are the breaker positions of all branch lines in the power distribution network, the meter box positions and the like, can be set freely according to the field conditions, and are not limited.
The detection module 5 is used for detecting voltage data and current data of the distribution line; in particular, the detection module 5 uses detection devices commonly used in the art, and needs to be ensured to be able to detect voltage data and current data of the distribution line. Preferably, the detection module 5 should include a current transformer and a voltage transformer or corresponding detection devices capable of detecting current data and voltage data. Further, the detection module 5 transmits the detected voltage data and current data to the electric energy metering module 4 to complete basic metering of the data, wherein a metering method commonly used in the art can be used as the metering method.
The fault studying, judging and positioning module 3 is configured to identify fault information according to the voltage data and the current data, and send the fault information to the processing module 7; specifically, the fault location module 3 is implemented by using a fault location device commonly used in the art, and certainly, each component completing the corresponding fault location function may be used to form a corresponding circuit structure to be connected to a system circuit of the circuit breaker, and is set according to the specific requirements without limitation;
the electric energy metering module 4 is used for identifying fault information according to the voltage data and the current data to form metering data and sending the metering data to the processing module 7; specifically, the electric energy metering module 4 is preferably a metering chip commonly used in the field or an MCU with a certain metering program, and the specific model is not limited, and is more preferably a multifunctional high-precision three-phase electric energy dedicated metering chip with the model of HT 7132.
The processing module 7 drives the low-current topological signal injection module 1 and the low-current topological signal identification module 2 to work normally, receives the fault information and the metering data, and performs information interaction with a server through the communication module 6. Specifically, the processing module 7 is an MCU or a CPU commonly used in the art, the specific model is not limited, and the corresponding functional tasks are completed through a built-in program or software. It should be noted that the low-current topology signal injection module 1 is driven and controlled by the processing module 7, that is, the information attached to the topology signal injected into the distribution line by the low-current topology signal injection module 1 is determined by the processing module 7, and the determined rule is not limited, where the determined rule is an information compiling rule of the topology signal, for example, a specific data number is transmitted in a binary manner, where the binary data implementation is realized by whether the low-current signal of adjacent detection time is realized at a certain detection frequency, specifically, a communication manner commonly used in the art is used, and this is merely an example; of course, the low-current topological signal identification module 2 also inputs the low-current signal identified in the distribution line into the processing module 7, and the processing module 7 identifies the corresponding topological signal information according to the above determination rule. Further, the communication module 6 is a communication device commonly used in the art, and is not particularly limited, and may be a wired communication (e.g., RS485, RS232, etc.) or a wireless communication (e.g., internet communication, GPRS communication, etc.), and further preferably, the communication module 6 is a wireless communication device, and preferably, the internet of things communication module 6 is used, and may be formed by an HPLC + master-slave integrated bluetooth module. Further, the processing module 7 further performs fault protection operations, such as electronic shunt tripping and electromagnetic tripping, according to the fault information, where the corresponding fault protection operations are implemented by processing a switching-closing mechanism of the driving circuit breaker, and the switching-closing mechanism is a basic configuration of a circuit breaker commonly used in the art, which is not limited in the present invention.
In specific implementation, the circuit breaker provided by the invention meets the future market demand, can form an industrial standard intelligent circuit breaker for the power internet of things, integrates functions and applications of topology injection, topology identification, voltage and current real-time data monitoring, electric energy metering, fault type study and judgment, positioning, protection and the like, improves the intelligent sensing capability of a data source, and realizes panoramic sensing and visual monitoring; meanwhile, all functional modules can be integrated based on miniaturization design, the limited space inside the molded case circuit breaker is reasonably utilized, circuit breaker faults such as heating and the like can not be caused, the circuit breaker is guaranteed to normally realize the work such as topology recognition, data measurement and fault recognition on the basis of not influencing a power distribution network, and the system requirements of the ubiquitous power internet of things and the digital power grid are met.
As a preferred scheme, please refer to fig. 2, in this embodiment, the low-current topology signal injection module 1 includes an injection optocoupler, a full-bridge rectification unit, and a signal generation switch; the full-bridge rectifying unit is connected with the secondary side of the injection optocoupler through the signal generation switch, and meanwhile, the full-bridge rectifying unit is connected into a single-phase loop of a distribution line; and the primary side of the injection optocoupler is connected with the processing module 7. Specifically, the injection optocoupler D1 is an isolation optocoupler to realize strong and weak current isolation; the left side of injecting the opto-coupler connects behind the pressure-sensitive for commercial power L, N obtain voltage signal V1 behind the full-bridge rectifier unit, and resistance R1 is topology signal current-limiting resistor for protection circuit, signal generation switch Q1 takes place the switch tube for the topology signal, by pull-up resistance R2, pull-down resistance R6, filter capacitor C2, the switch tube drive circuit that resistance R4 constitutes. And on the right side of the injection optocoupler, a topology generation control signal of characteristic frequency is output for an MCU chip of the processing module 7, and the blocking filter circuit formed by a blocking capacitor C1, a filter resistor R5 and a filter capacitor C3 has good anti-shake and anti-interference capabilities. Preferably, the circuit of the low-current topology signal identification module 2 and the circuit of the low-current topology signal injection module 1 are designed in a matching manner, and a common matching design in the field may be specifically used, which is not described herein again.
The detection module 5 comprises a plurality of current transformers and a plurality of voltage sensors, and is respectively connected with the fault studying and judging and positioning module 3 and the electric energy metering module 4. The current transformer with voltage sensor's quantity can be the same, also can not be the same, can how much do corresponding configuration according to the circuit of distribution network, also can freely set for according to the circuit quantity that inserts the position, simultaneously can also detachable dismantle or install convenient and fast, accords with the demand of miniaturized equipment simultaneously. Referring to fig. 3, taking the current data detection circuit of a matching circuit as an example for specific description, taking the current data IA of an a-phase circuit as an example, a differential circuit is adopted, and the secondary of the current transformer CT _ Sampling is connected to the high-precision Sampling resistor R102 and the Sampling resistor R106 which are symmetrically arranged, and enters the differential Sampling input port of the metering chip U2(HT7132) after being filtered by the RC formed by the filter resistor R101, the filter resistor R109, the filter capacitor C101 and the filter capacitor C103. Referring to fig. 5, the metering chip U2 is a multifunctional high-precision metering chip dedicated for three-phase electric energy, and is suitable for three-phase three-wire and three-phase four-wire applications, and the preferred model is HT7132, and integrates 7-way 22-bit ADCs, a reference voltage circuit, and all circuits for digital signal processing for power, energy, effective value, power factor, and frequency measurement, and the like, so as to measure active power, reactive power, apparent power, active function quantity, and reactive energy of each phase and a combined phase, and simultaneously measure parameters of each phase current, voltage effective value, power factor, phase angle, frequency, and the like, and fully meet the requirements of a three-phase multi-rate multifunctional electric energy meter. The measuring chip U2 provides two SPI interfaces, including a common SPI port and a high-speed interface HSDC, conveniently with the transmission of measurement and school table parameter between the outside MCU, the concrete specification of SPI interface refers to SPI detailed description part, all measurement parameters and school table parameter all can read out through the SPI interface. The high-speed interface HSDC is convenient for transmitting the sampling data to the main MCU at high speed, namely the processing module 7, the main MCU extracts the topological characteristic signal to realize topological identification, and the judging conditions comprise phase difference, current value range and characteristic signal frequency. Further, in order to realize high-precision sampling and high-efficiency electricity taking, the current transformers are at least two groups of transformers which are respectively sampling transformers and electricity taking transformers. The sampling mutual inductor adopts a high-precision current mutual inductor formed by winding a circular closed magnetic core, and the mutual inductor is placed in a matched plastic shell and fixed by pouring sealant, so that the stability and the reliability are realized. A secondary side port of the current transformer is connected with a sampling circuit to realize high-precision metering, topological signal sampling and fault current sampling, the preferred specification model is that a metering sampling measurement value can reach 2 times of rated current, a fault current sampling measurement value can reach more than 12 times of rated current, and the wide range of a fault protection setting value can be set. The three kinds of sampling of metering, topology identification signal and fault protection share the same set of high-precision mutual inductor and sampling resistor, but because the measurement key points and the measurement ranges of all the functional modules are obviously different, different channels of the detection module 5 are connected, and the connection mode commonly used in the field is specifically used. The fault studying, judging and positioning module 3 comprises a plurality of identical studying and judging units; the judging unit comprises an operational amplifier, the input end of the operational amplifier is connected with the detection module 5, and the output end of the operational amplifier is connected with the processing module 7. Specifically, referring to fig. 4, in the circuit diagram of the judging unit in this embodiment, the fault protection loop in the fault judging and positioning module 3 enters the internal ADC of the main MCU (i.e., the processing module 7) after being conditioned by the operational amplifier and the peripheral circuit, so as to implement fault protection sampling, and the judging unit performs the judging according to the set fault setting value. The judging capacitor C202 has the function of blocking direct current and alternating current, and the voltage follower has the characteristics of high input impedance and low output impedance, so that after the 1.2V bias voltage passes through the judging resistor R203, the bias voltage is added to the alternating current signal after the judging capacitor C202, and the alternating current signal before the judging capacitor C202 is not influenced. The voltage dividing circuit composed of the judging resistor R205 and the judging resistor R203 can adjust the proportion to adjust the amplitude of the sampling signal so as to adapt to circuit breakers with different current specifications. The voltage is then connected with an RC filter circuit of a judging resistor R204 and a judging capacitor C204 and then enters an ADC channel of the main MCU.
Correspondingly, the invention also provides a low-voltage power distribution network system which comprises a fusion terminal and a plurality of circuit breakers; the circuit breakers are respectively arranged at a plurality of key nodes in a distribution network topological structure and are connected to a distribution network;
the fusion terminal is arranged at the node position of the transformer area, is in communication connection with the circuit breaker at the current node position, and is used for acquiring the topological structure of the transformer area and monitoring the faults of the transformer area.
Specifically, referring to fig. 6, all the connected circuit breakers are required to work cooperatively when the low-voltage distribution network is normally monitored, and each circuit breaker is used in cooperation with the low-current topological signal injection module 1 and the low-current topological signal identification module 2, that is, two function modules are configured on each key node in the distribution network, so that topology detection and topology signal injection of downstream equipment by a current key position can be realized, and further, the identification of a topological structure is quickly realized on the basis of not affecting the distribution network. At this time, the identification of the topology structure also requires a corresponding processing center to perform comprehensive processing and analysis of data, and the specific analysis method may use a topology identification method commonly used in the art, which is not specifically limited in this embodiment. The key nodes are the breaker positions of all branch lines in the power distribution network, the meter box positions and the like, can be set freely according to the field conditions, and are not limited. The low-voltage distribution network system provided by the invention can realize the visual monitoring of the transformer area, solves the problem of fuzzy relation of 'house-transformer' and 'house-box-transformer' of the low-voltage distribution network by adopting topology injection and identification technologies, and realizes that 'transformer, line, box and house' can be observed and measured, thereby improving the power supply service capability.
As a preferred solution, in this embodiment, the step of acquiring the platform area topology structure includes:
sequentially starting circuit breakers at end node positions to inject a small current topological signal attached with current meter information into the power distribution network;
the breaker which receives the small current topological signal adds the table information and then sends the small current topological signal to the power distribution network again;
and sending the collected circuit breakers at the node positions of the transformer in the transformer area to the fusion terminal to form a topological structure of the power distribution network.
The basic principle of the topological structure identification process is as follows: the intelligent circuit breaker is internally integrated with a small current characteristic signal generating and identifying circuit, an intelligent circuit breaker with an encryption function in a terminal user meter box is communicated with a user meter through RS485 to read a meter address, a maintainer is connected with a master-slave integrated Bluetooth module arranged in the intelligent circuit breaker through a handheld Bluetooth device to input position information of 'X area-X building number-X meter box', the intelligent circuit breaker supports the monitoring master station to carry out time comparison, the characteristic signal is injected at a certain moment, the characteristic signal only circulates along a circuit between the intelligent circuit breaker and a transformer, a branch line is not crossed, a transformer area is not crossed, the intelligent circuit breaker collects current data in real time, the topological signal can be collected and identified by only the intelligent circuit breaker in the circuit at the moment, after the identification is successful, the information such as the address, the identification time, the current and the like is uploaded to a fusion terminal or an energy source controller through HPLC to be subjected to total analysis, and judging the upper-level and lower-level relations according to the current, namely finishing the topological structure of the route, and by analogy, finally generating a complete distribution area electrical topological structure to realize visual monitoring, and quickly positioning a fault point if a fault occurs. In addition, if a new or changed user meter is accessed subsequently, the intelligent circuit breaker can identify a new address and automatically trigger a change information uploading master station to realize automatic updating of the topological structure only by communicating with the intelligent circuit breaker in the meter box locally through RS 485. The low-voltage distribution network system provided by the invention has the advantages that: the topological function is integrated in the intelligent circuit breaker, so that external auxiliary equipment is avoided; the low-current topological mode is adopted, and the influence on a power grid is almost avoided; the injected high-frequency characteristic signal has better anti-interference capability and can realize effective information transmission.
Correspondingly, the invention also provides a low-voltage distribution network fault monitoring method suitable for the low-voltage distribution network system, which comprises the following steps:
the circuit breakers of all key nodes determine fault types according to the acquired voltage data and current data; preferably, the fault types include: three phase fault, two phase short circuit, relative neutral fault, relative earth fault.
And uploading the fault type data, the current data, the voltage data and the parameter data to the fusion terminal.
Specifically, referring to fig. 7 and 8, each stage of circuit breaker is installed on a line at different positions to implement segment protection, and the current fault types include a three-phase short circuit, a two-phase short circuit, a single-phase short circuit, and a single-phase ground. The circuit breaker protection setting value is reasonably set to realize stable and reliable protection, all levels can be coordinated and matched, the upper and lower actions have selectivity, namely the fault current value of a fault point is preferentially cut off by the circuit breaker of the upper level closest to the fault point to reduce the power failure range. The TT and TN system is commonly used to low voltage distribution network, and when distribution lines had certain length when distribution lines, the influence of line impedance to short-circuit current size was not neglected, generally used line head end three-phase short-circuit current as the biggest, used terminal single-phase ground connection short-circuit fault current as the minimum.
And calculating theoretical impedance and theoretical fault current value of each line position according to the measurement data and a formula.
The pre-ground fault current calculation formula of each fault type is as follows:
Isc3 three-phase short circuit＝U20/(√3*Zsc)；
Isc2 two-phase short circuit＝U20/(2*Zsc)；
Isc1 single-phase to neutral short circuit＝U20/(√3*(Zsc+ZLn))；
Isc0 single-phase grounding＝U20/(√3*(Zsc+Z(0)))；
Wherein, U20Is the voltage of a no-load line at the secondary side of the transformer; i isscShort circuit current (short circuit); zscIs the line impedance; zLnIs the neutral line impedance; z(0)The ground impedance may include system operation ground impedance, enclosure protection ground impedance, and high-impedance ground impedance.
And (3) impedance calculation:
impedance of low voltage side of transformer: calculating the equivalent impedance, Z, from the percentage of impedance voltage and the capacity marked on the nameplate of the transformerT＝ΔUk％*Un^2/Pr(ii) a Wherein, Delta Uk% change in impedance voltage, UnAt nominal phase voltage, PrIs rated capacity.
Calculating the impedance of each section of line: zUpper level-lower level＝(USuperior level-ULower level)/ILower level(ii) a Such as ZL1＝(U1-U2)/I2；
Fault protection setting value:
and (3) calculating theoretical fault current of each section of line according to the transformer capacity of the transformer area and the fault loop impedance to set the protection setting value of the circuit breaker, wherein the protection setting value comprises instantaneous overcurrent, short delay, long delay and leakage current.
The protection setting value Iset of the circuit breaker is less than or equal to 1.3 times of fault current
For segment protection, the upper and lower actions should be selective, IsetShort time delay of upper level≥1.2*IsetLower level transient；
For a low-voltage distribution line with short length, the current of the ground fault at the tail end of the distribution line is large, and the method of adopting the instantaneous overcurrent of the circuit breaker and the ground fault protection is easy to realize.
For a low-voltage distribution line with a long length, the end of the distribution line has a small ground fault current, or for a high-resistance ground fault, the fault current is small. The instantaneous overcurrent method using a circuit breaker cannot be used as ground fault protection at the same time. Residual current transformers and circuits are needed to realize leakage protection.
In order to avoid false operation, the residual current protection setting value Iset of the circuit breaker is 2.5-4 times larger than the sum of leakage currents of lines and equipment in normal operation, and I is satisfiedSingle-phase groundingAnd more than or equal to 1.3 Iset, and setting the action setting current value to be 0.5A if the action setting current value is set.
And (3) fault study, judgment and positioning:
when a fault occurs, the breaker acquires voltage and current, the fault type can be judged according to the acquired fault time data and the state of each phase, and if the three phases exceed a short-circuit fault current setting value, a three-phase short circuit is defined; if both phases exceed the short-circuit fault current setting value, defining the two phases as short circuits; if the single phase exceeds the earth fault current setting value, defining the single phase as single phase earth; if the phase current has no obvious fault current and only the residual current fault is judged, the single-phase high-resistance grounding is defined.
The breaker uploads not only power failure events and fault types, but also voltage and current data at the moment of the fault, wherein the fault types are uploaded so that maintenance personnel can carry out targeted emergency repair; wherein upload the data at trouble moment, through gathering analysis processes can not only fix a position the fault line section fast and be between two circuit breakers of upper and lower level, and can realize accurate study and judge fault point position X, the formula is as follows:
Usuperior level-ISuperior level*Zsuperior-X＝ULower level+ILower level*(ZUpper level-lower level-Zsuperior-X)；
Lsuperior-X＝Zsuperior-X*(LUpper level-lower level/ZUpper level-lower level)；
Known as USuperior level、ISuperior level、ULower level、ILower level、ZUpper level-lower level、LUpper level-lower level；
Then, L can be obtainedsuperior-X。
In summary, the circuit breaker, the low-voltage distribution network system and the fault monitoring method provided by the invention have the following advantages: 1. highly integrated's small-size intelligent circuit breaker, with topology injection, topology discernment, voltage and current real-time data monitoring, electric energy measurement, functions and application collection such as fault type are studied and judged, location and protection as an organic whole, promote the intelligent perception ability of data source, realize panorama perception and visual monitoring. 2. The topological function is integrated in the intelligent circuit breaker, so that external auxiliary equipment is avoided; the power grid is almost not influenced by a built-in low-current topological injection mode; the injected high-frequency characteristic signals have good anti-interference capability and can realize effective information transmission, the problem of fuzzy relation of 'household-transformer' and 'household-box-transformer' of the low-voltage distribution network is solved, and the 'transformer, line, box and household' can be observed and measured, so that the power supply service capability is improved. 3. In order to meet the requirements of small size and function integration, three kinds of sampling of metering, topology identification and fault protection share the same set of high-precision mutual inductor and sampling resistor, the high-precision metering, topology identification and fault current sampling are realized by utilizing a simplified conditioning circuit and elements, the mutual inductor is placed in a matched plastic shell and is fixed by pouring sealant, and the stability and reliability are realized. 4. Fault current is pre-researched, a protection setting value is reasonably set to realize stable and reliable protection, all stages can be coordinated and matched, and the actions of the upper stage and the lower stage have selectivity. 5. The method realizes the study and judgment of fault types and the location of fault positions, and obviously improves the power failure emergency repair efficiency.
It should be understood that equivalents and modifications of the technical solution and inventive concept thereof may occur to those skilled in the art, and all such modifications and alterations should fall within the scope of the appended claims.
Claims (10)
1. A circuit breaker is characterized by comprising a low-current topological signal injection module, a low-current topological signal identification module, a fault study and judgment positioning module, an electric energy metering module, a detection module, a communication module and a processing module;
the low-current topological signal injection module is used for injecting a low-current topological signal into the power distribution network according to the instruction of the processing module;
the small current topological signal identification module is used for receiving and identifying a small current topological signal in the power distribution network and transmitting the small current topological signal to the processing module;
the detection module is used for detecting voltage data and current data of the distribution line;
the fault studying, judging and positioning module is used for identifying fault information according to the voltage data and the current data and sending the fault information to the processing module;
the electric energy metering module is used for identifying fault information according to the voltage data and the current data to form metering data and sending the metering data to the processing module;
the processing module drives the low-current topological signal injection module and the low-current topological signal identification module to normally work, receives the fault information and the metering data, and simultaneously performs information interaction with a server through the communication module.
2. The circuit breaker of claim 1, wherein the low-current topology signal injection module comprises an injection optocoupler, a full-bridge rectification unit, and a signal generation switch; the full-bridge rectifying unit is connected with the secondary side of the injection optocoupler through the signal generation switch, and meanwhile, the full-bridge rectifying unit is connected into a single-phase loop of a distribution line; and the primary side of the injection optocoupler is connected with the processing module.
3. The circuit breaker of claim 1, wherein the detection module comprises a plurality of current transformers and a plurality of voltage sensors, each connected to the fault location module and the power metering module, respectively.
4. The circuit breaker of claim 1, wherein the fault judging and positioning module comprises a plurality of identical judging units; the judging unit comprises an operational amplifier, the input end of the operational amplifier is connected with the detection module, and the output end of the operational amplifier is connected with the processing module.
5. The circuit breaker of claim 1, wherein the power metering module is a metering chip; the model of the metering chip is HT 7132.
6. The circuit breaker of claim 1, wherein the communication module is a wireless communication device.
7. A low voltage power distribution network system comprising a convergence terminal and a plurality of circuit breakers as claimed in any one of claims 1 to 6; the circuit breakers are respectively arranged at a plurality of key nodes in a distribution network topological structure and are connected to a distribution network;
the fusion terminal is arranged at the node position of the transformer area, is in communication connection with the circuit breaker at the current node position, and is used for acquiring the topological structure of the transformer area and monitoring the faults of the transformer area.
8. The low voltage power distribution network system of claim 7, wherein the acquisition step of the platform topology is:
sequentially starting circuit breakers at end node positions to inject a small current topological signal attached with current meter information into the power distribution network;
the breaker which receives the small current topological signal adds the table information and then sends the small current topological signal to the power distribution network again;
and sending the collected circuit breakers at the node positions of the transformer in the transformer area to the fusion terminal to form a topological structure of the power distribution network.
9. A method for fault monitoring of a low voltage distribution network suitable for use in a low voltage distribution network system according to any of claims 7-8, comprising the steps of:
the circuit breakers of all key nodes determine fault types according to the acquired voltage data and current data;
and uploading the fault type data, the current data, the voltage data and the parameter data to the fusion terminal.
10. Method for fault monitoring of a low voltage distribution network according to claim 9, characterized in that the fault types comprise: three phase fault, two phase short circuit, relative neutral fault, relative earth fault.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114157031A (en) * | 2021-12-03 | 2022-03-08 | 国网湖南省电力有限公司 | Circuit breaker fault processing device and method of power internet of things |
| CN114236458A (en) * | 2021-11-18 | 2022-03-25 | 深圳供电局有限公司 | Method and device for positioning fault of double-core intelligent ammeter based on test data stream |
| CN114660381A (en) * | 2022-03-09 | 2022-06-24 | 南阳理工学院 | Power line branch monitoring terminal and impedance analysis method thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111352028A (en) * | 2020-04-14 | 2020-06-30 | 山东德源电力科技股份有限公司 | Molded case circuit breaker and line loss analysis method |
| CN111863559A (en) * | 2020-07-03 | 2020-10-30 | 威胜信息技术股份有限公司 | Low-voltage Internet of things breaker and fault detection method thereof |
| CN112187518A (en) * | 2020-09-07 | 2021-01-05 | 佳源科技有限公司 | Intelligent fusion terminal platform area topology identification method and system |
-
2021
- 2021-02-25 CN CN202110210121.9A patent/CN112803597A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111352028A (en) * | 2020-04-14 | 2020-06-30 | 山东德源电力科技股份有限公司 | Molded case circuit breaker and line loss analysis method |
| CN111863559A (en) * | 2020-07-03 | 2020-10-30 | 威胜信息技术股份有限公司 | Low-voltage Internet of things breaker and fault detection method thereof |
| CN112187518A (en) * | 2020-09-07 | 2021-01-05 | 佳源科技有限公司 | Intelligent fusion terminal platform area topology identification method and system |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114236458A (en) * | 2021-11-18 | 2022-03-25 | 深圳供电局有限公司 | Method and device for positioning fault of double-core intelligent ammeter based on test data stream |
| CN114157031A (en) * | 2021-12-03 | 2022-03-08 | 国网湖南省电力有限公司 | Circuit breaker fault processing device and method of power internet of things |
| CN114660381A (en) * | 2022-03-09 | 2022-06-24 | 南阳理工学院 | Power line branch monitoring terminal and impedance analysis method thereof |
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