CN112467696B - Power distribution system management device and method - Google Patents

Power distribution system management device and method Download PDF

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Publication number
CN112467696B
CN112467696B CN202011122995.0A CN202011122995A CN112467696B CN 112467696 B CN112467696 B CN 112467696B CN 202011122995 A CN202011122995 A CN 202011122995A CN 112467696 B CN112467696 B CN 112467696B
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Prior art keywords
power distribution
distribution system
system management
management device
cabinet
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CN112467696A (en
Inventor
谢剑南
傅佳琪
余成
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Ningbo Dajia Xiaojia Network Technology Co ltd
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Ningbo Dajia Xiaojia Network Technology Co ltd
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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/22—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices
    • 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
    • H02J13/00006—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 information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
    • H02J13/00016—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 information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment using a wired telecommunication network or a data transmission bus
    • 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
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/001—Methods to deal with contingencies, e.g. abnormalities, faults or failures
    • H02J3/00125—Transmission line or load transient problems, e.g. overvoltage, resonance or self-excitation of inductive loads
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/20—Systems supporting electrical power generation, transmission or distribution using protection elements, arrangements or systems
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S40/00—Systems for electrical power generation, transmission, distribution or end-user application management characterised by the use of communication or information technologies, or communication or information technology specific aspects supporting them
    • Y04S40/12—Systems for electrical power generation, transmission, distribution or end-user application management characterised by the use of communication or information technologies, or communication or information technology specific aspects supporting them characterised by data transport means between the monitoring, controlling or managing units and monitored, controlled or operated electrical equipment
    • Y04S40/124—Systems for electrical power generation, transmission, distribution or end-user application management characterised by the use of communication or information technologies, or communication or information technology specific aspects supporting them characterised by data transport means between the monitoring, controlling or managing units and monitored, controlled or operated electrical equipment using wired telecommunication networks or data transmission busses

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Remote Monitoring And Control Of Power-Distribution Networks (AREA)

Abstract

The invention discloses a power distribution system management device and method, comprising a main chip, a network module connected with the main chip, a storage module, a signal conditioning module and an on-off detection module; the main chip receives the electrical data of the signal conditioning module and the on-off detection module and buffers the electrical data in the storage module; the main chip is in communication connection with a power distribution system management device and a power distribution system server on other power distribution cabinets through the network module, receives and/or issues instructions, and uploads the electrical data cached in the storage module to the power distribution system server. The power distribution system management device and the power distribution system management method can ensure the stability and the reliability of the power distribution system, avoid power failure accidents caused by overload or short circuit of the power distribution system, analyze fault points in a short time when faults occur, greatly improve the maintenance efficiency and reduce economic loss and safety accident risks caused by power failure maintenance of users.

Description

Power distribution system management device and method
Technical Field
The invention relates to a power distribution system management device and method, and belongs to the technical field of power distribution equipment intellectualization.
Background
Overload and short circuit occur in the existing power distribution system, and large-area power failure accidents can be caused under severe conditions, so that large economic losses are caused. The service personnel need to repair the fault in time whenever a trip occurs to restore power.
Overload is generally caused by excessive load access at the user side, so that power distribution equipment in a certain power distribution cabinet exceeds an allowable current value, and then a protection device in the power distribution cabinet automatically cuts off lines so that all lower-level power distribution cabinets of the power distribution cabinet are powered off. Assuming that the load current of the low-voltage incoming line cabinet exceeds the overload long-time-delay current set value on the circuit breaker controller, a protection device on the low-voltage incoming line cabinet enters tripping protection countdown, and after the tripping protection action of the low-voltage incoming line cabinet, all outgoing line cabinet lines at the lower stage are powered off, so that a large amount of money is lost for production and life of users. For such a situation, the service personnel will confirm with the user that a certain less important outlet cabinet is cut off and then the circuit breaker of the outlet cabinet is closed to restore the power supply. Or the overhauling personnel sets the overload long-time-delay current set value on the low-voltage incoming circuit breaker to be large, but the ageing of the transformer is accelerated in this way, and the processing mode does not meet the safety specification.
The problem that the distribution system cannot avoid aging or being bitten by small animals in long-time operation can cause the problem that the distribution equipment is in interphase short circuit or in ground short circuit. The traditional industry can only cut off the short-circuit current by the protection mechanism of the high-voltage microcomputer protection or the low-voltage switch. The traditional protection mechanism can only indicate that a fault point occurs at a certain place under the bus line, and cannot give an accurate fault range. If the fault point is to be found accurately, the short-circuit fault point can be found only by the experience and technical ability of electricians through a large amount of time. Usually, the fault point of the short circuit needs to be checked by means of equipment such as a universal meter and the like, and the fault point is checked line by line. Such a removal method is very inefficient and fails to locate the failure point in time resulting in a longer outage time leading to greater economic losses.
Disclosure of Invention
The invention aims to provide a power distribution system management device and method, which are used for solving the problem of power failure accidents caused by overload or short circuit of a power distribution system in the prior art.
In order to achieve the above purpose, the invention is realized by adopting the following technical scheme:
in a first aspect, the invention provides a power distribution system management device, which comprises a main chip, a network module connected with the main chip, a storage module, a signal conditioning module and an on-off detection module;
the main chip receives the electrical data of the signal conditioning module and the on-off detection module and buffers the electrical data in the storage module;
the main chip is in communication connection with a power distribution system management device and a power distribution system server on other power distribution cabinets through the network module, receives and/or issues instructions, and uploads the electrical data cached in the storage module to the power distribution system server.
In combination with the first aspect, further, the network module includes a USB serial port, a CAN interface, and an ethernet interface, where the USB serial port is in communication connection with an upper computer of the power distribution system management device, the CAN interface is in communication connection with the power distribution system management devices on other power distribution cabinets, and the ethernet interface is in communication connection with a power distribution system server.
Preferably, the network module further comprises an RS485 interface, and the RS485 interface is in communication connection with a dehumidifier of the power distribution system.
Preferably, the CAN interface is also capable of receiving time service data of the GPS/Beidou positioning receiver.
With reference to the first aspect, further, an input end of the signal conditioning module is connected with a voltage current transformer, and the signal conditioning module transmits signals collected by the voltage current transformer to the main chip through signal conditioning.
With reference to the first aspect, the on-off detection module further includes at least one current limiting circuit and at least one micro optical coupler, the current limiting circuit processes the signal of the target loop into a size that can be detected by the micro optical coupler, and the main chip detects on-off of the target loop through the micro optical coupler.
Preferably, the main chip is internally provided with a high-speed AD unit and a DSP unit, the high-speed AD unit is connected with the output end of the signal conditioning module, the high-speed AD unit converts a circuit signal from an analog quantity to a data quantity, and the DSP unit processes the circuit signal of the data quantity into electric data which is convenient for the main chip to process.
Preferably, the memory module comprises an EEPROM and an external flash. The EEPROM is used for storing system parameters, user configuration parameters and electric quantity information; the external flash is used for storing alarm information fault wave recording data and protection fixed value data and bill of materials data.
In a second aspect, the present invention further provides a power distribution system management method, which is implemented by any one of the following methods:
method a: the power distribution system management device acquires three-phase current values, and judges whether overload linkage protection is started or not according to the maximum current value;
method b: the power distribution system management device caches the electrical data, and judges whether to freeze the cached data and whether to start quick-break tripping protection according to the electrical data in the current circuit.
With reference to the second aspect, further, the method a includes:
the power distribution system management device obtains three-phase current values, finds a maximum current value I, and judges the magnitudes of the maximum current value I and an overload long-delay current setting value I:
if I is more than or equal to I, the power distribution system management device starts a timer function to count time, calculates tripping time T, and compares whether the difference value between the current timer value and the current timer value is smaller than a set threshold value; if the difference value is smaller than the set threshold value, starting linkage protection logic; if the difference value is greater than or equal to the set threshold value, continuously acquiring a three-phase current value;
if I is less than I, closing the function of the timer to clear the time, and continuously obtaining the three-phase current value.
With reference to the second aspect, further, the method b includes:
the power distribution system management device caches the electrical data and judges whether the current electrical quantity meets the quick-break tripping condition or not:
if the quick-break tripping condition is met, notifying a lower-level power distribution system management device to freeze the cached electric data and uploading the frozen cached electric data to a power distribution system server, and executing tripping operation; after the cutting-off is finished, the power distribution system management device performs fault information input and wave recording, and the fault information is uploaded to a power distribution system server;
if the quick breaking tripping condition is not met but an instruction for freezing and caching the electrical data sent by the upper-level power distribution system management device is received, the electrical data are frozen and cached, and the frozen and cached electrical data are uploaded to a power distribution system server;
and if the quick-break tripping condition is not met and the instruction for freezing the cache data is not received, continuing to circularly store the subsequent electrical data.
In combination with the second aspect, the method further comprises the steps of establishing a data model of mutual communication of distribution system management devices in the distribution system, configuring electrical level codes for each device of the distribution system, packaging the coded information into an ID of a CAN extension frame, and transmitting data of the distribution system management devices through a data frame carrier to realize data sharing and distribution among the distribution system management devices.
With reference to the second aspect, further, the calculation formula for calculating the trip time T is:
i represents the maximum value of three-phase instantaneous current values collected by a power distribution system management device, I represents an overload long-delay current setting value, T represents an overload long-delay time setting value, and T represents the tripping time of a circuit breaker.
In combination with the second aspect, the linkage protection logic further comprises sequentially issuing tripping instructions according to the priority of the lower-level power distribution cabinet set by a user, and the total load of the power distribution cabinet main cabinet is reduced until the important line can be ensured not to be powered off.
Compared with the prior art, the invention at least has the following beneficial effects:
the invention is provided with a main chip, a network module connected with the main chip, a storage module, a signal conditioning module and an on-off detection module, and starts linkage protection logic under the overload condition of the power distribution cabinet, and the lower power distribution cabinet is sequentially disconnected according to the priority set by a user so as to reduce the total load of the total cabinet, ensure the stability and reliability of the operation of the total cabinet, avoid unnecessary power failure accidents, reduce economic loss caused by power failure and reduce the safety accident risk caused by power failure;
according to the invention, each level of management device is communicated with the power distribution system server through the CAN bus of the network module, and is communicated with the power distribution system server through the Ethernet of the network module, when an electrical short circuit fault occurs in a circuit, the electrical data at the moment of the fault is frozen and uploaded to the power distribution system server, the power distribution system server CAN analyze the occurrence of the fault in a short time, the maintenance efficiency is greatly improved, and the economic loss and the safety accident risk caused by power failure maintenance of a user are reduced;
the management devices at all levels communicate through the CAN bus of the network module, so that the wiring cost is low, and the real-time performance and reliability CAN be ensured.
Drawings
Fig. 1 is a block diagram of a power distribution system management device according to a first embodiment of the present invention;
fig. 2 is a schematic application diagram of a power distribution system management device according to a first embodiment of the present invention;
fig. 3 is a flowchart of overload linkage protection of a power distribution system management method according to a second embodiment of the present invention;
fig. 4 is a flowchart of a short-circuit fault protection of a power distribution system management method according to a second embodiment of the present invention;
fig. 5 is an electrical hierarchy coding rule diagram of a power distribution system management method according to a second embodiment of the present invention;
fig. 6 is a CAN extended frame ID allocation diagram of a power distribution system management method according to a second embodiment of the present invention;
fig. 7 is a power distribution structure of a power distribution system management method according to a third embodiment of the present invention;
fig. 8 is a flowchart of an execution of a circuit system power distribution system server in short-circuit fault protection of a power distribution system management method according to a third embodiment of the present invention;
fig. 9 is a block diagram of cached data frozen by a power distribution system management device in a power distribution system management method according to a third embodiment of the present invention;
fig. 10 is a visual chart of cached data frozen by a power distribution system management device in a power distribution system management method according to a third embodiment of the present invention;
fig. 11 is an example of an electrical hierarchy code of a power distribution system management device in a power distribution system management method according to a third embodiment of the present invention.
Detailed Description
The invention is further described below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present invention, and are not intended to limit the scope of the present invention.
In the description of the present invention, the orientation or positional relationship indicated by the terms "upper", "bottom", etc. are based on the orientation or positional relationship shown in the drawings, and are merely for convenience of describing the present invention and do not require that the present invention must be patterned and operated in a specific orientation, and thus should not be construed as limiting the present invention.
Embodiment one:
as shown in fig. 1, an embodiment of the present invention provides a power distribution system management device, including a main chip, a network module connected with the main chip, a storage module, a signal conditioning module, and an on-off detection module;
the main chip receives the electrical data of the signal conditioning module and the on-off detection module and buffers the electrical data in the storage module;
the main chip is in communication connection with a power distribution system management device and a power distribution system server on other power distribution cabinets through the network module, receives and/or issues instructions, and uploads the electrical data cached in the storage module to the power distribution system server.
Specifically, the main chip is an ARM architecture singlechip with a built-in high-speed AD unit and a built-in DSP unit. The high-speed AD unit is connected with the output end of the signal conditioning module, the high-speed AD unit converts a circuit signal from an analog quantity to a data quantity, and the DSP unit processes the circuit signal of the data quantity into electric data which is convenient for the main chip to process. In this embodiment, the model of the main chip is: STM32F407ZGT6.
The input end of the signal conditioning module is connected with at least one group of voltage and current transformers, and the signal conditioning module transmits signals acquired by the voltage and current transformers to the high-speed AD unit of the main chip through signal conditioning.
Specifically, the voltage-current transformer includes: the integrated operational amplifier is used for collecting temperature signals and Rogowski coil signals, a miniature voltage transformer used for collecting voltage sampling signals, a miniature current transformer used for measuring current sampling signals and a miniature current transformer used for collecting protection current sampling signals.
The on-off detection module comprises at least one current limiting circuit and at least one miniature optical coupler, the current limiting circuit processes a signal of the target loop into a size which can be detected by the miniature optical coupler, and the main chip detects on-off of the target loop through the miniature optical coupler.
Specifically, because the strong current switch signals, such as a voltage-losing alarm signal, a switching-on loop and a switching-off loop signal are all 110V-220V, the optocoupler is required to be driven after a current-limiting resistor to realize the on-off detection of the singlechip. The other passive switch signals such as a switch handcart and the like directly control the optical coupler to be connected so as to realize the detection of the singlechip.
The network module comprises a USB serial port, a CAN interface, an Ethernet interface and an RS485 interface, wherein the USB serial port is in communication connection with an upper computer of the power distribution system management device, the CAN interface is in communication connection with the power distribution system management devices on other power distribution cabinets, the Ethernet interface is in communication connection with a power distribution system server, and the RS485 interface is in communication connection with a dehumidifier of the power distribution system. It should be noted that the CAN interface of the network module CAN also receive time service data of the GPS/Beidou positioning receiver.
The storage module comprises an EEPROM and an external flash. The EEPROM is used for storing system parameters, user configuration parameters and electric quantity information; the external flash is used for storing alarm information fault wave recording data and protection fixed value data and bill of materials data.
The power distribution system management device is arranged on the power distribution cabinet to monitor the whole power distribution system. An application scenario of the power distribution system management device is shown in fig. 2.
Example 2:
the embodiment of the invention provides a power distribution system management method, which is realized by adopting any one of the following methods:
method a: the power distribution system management device acquires three-phase current values, and judges whether overload linkage protection is started or not according to the maximum current value;
method b: the power distribution system management device caches the electrical data, and judges whether to freeze the cached data and whether to start quick-break tripping protection according to the electrical data in the current circuit.
As shown in fig. 3, the method a includes:
the power distribution system management device obtains three-phase current values, finds a maximum current value I, and judges the magnitudes of the maximum current value I and an overload long-delay current setting value I:
if I is more than or equal to I, the power distribution system management device starts a timer function to count time, calculates tripping time T, and compares whether the difference value between the current timer value and the current timer value is smaller than a set threshold value; if the difference value is smaller than the set threshold value, starting linkage protection logic; if the difference value is greater than or equal to the set threshold value, continuously acquiring a three-phase current value;
if I is less than I, closing the function of the timer to clear the time, and continuously obtaining the three-phase current value.
As shown in fig. 3, the linkage protection logic includes sequentially issuing trip instructions according to the priority of the lower power distribution cabinet set by the user, and the total load of the power distribution cabinet is reduced until the important line is ensured not to be powered off.
Specifically, the calculation formula for calculating the trip time T is:
i represents the maximum value of three-phase instantaneous current values collected by a power distribution system management device, I represents an overload long-delay current setting value, T represents an overload long-delay time setting value, and T represents the tripping time of a circuit breaker.
As shown in fig. 4, the method b includes:
the power distribution system management device caches the electrical data and judges whether the current electrical quantity meets the quick-break tripping condition or not:
if the quick-break tripping condition is met, notifying a lower-level power distribution system management device to freeze the cached electric data and uploading the frozen cached electric data to a power distribution system server, and executing tripping operation; after the cutting-off is finished, the power distribution system management device performs fault information input and wave recording, and the fault information is uploaded to a power distribution system server;
if the quick breaking tripping condition is not met but an instruction for freezing and caching the electrical data sent by the upper-level power distribution system management device is received, the electrical data are frozen and cached, and the frozen and cached electrical data are uploaded to a power distribution system server;
and if the quick-break tripping condition is not met and the instruction for freezing the cache data is not received, continuing to circularly store the subsequent electrical data.
In order to realize the data synchronization between the distribution system management devices, the method further comprises the steps of establishing a data model of the mutual communication of the distribution system management devices in the distribution system, configuring electrical level codes for each device of the distribution system, packaging the code information into the ID of the CAN extension frame, and transmitting the data of the distribution system management devices through a data frame carrier to realize the data sharing and distribution among the distribution system management devices.
The encoding rules are defined as shown in fig. 5. A first number is defined to represent the management voltage level of the current power distribution system management device, where 1 represents a 380 volt power distribution system, 2 represents a 6 kv power distribution system, 3 represents a 10kv power distribution system, and 4 represents a 35 kv power distribution system. Defining a second digit to represent the type of cabinet in which the current power distribution system management device is located, the cabinet can be currently classified into 7 categories (0 to represent an incoming cabinet, 1 to represent an outgoing cabinet, 2 to represent a tie cabinet, 3 to represent a capacitor cabinet, 4 to represent a power generation cabinet, 5 to represent a transformer cabinet, and 6 to represent an isolation cabinet). The third number is defined to represent the upper level number of the power distribution system management device. The fourth number indicates its own code. The codes of the two latter numbers refer to the numbers of a plurality of distribution system management devices under the same condition, for example, two outgoing distribution system management devices are connected behind the same 10 kilovolt incoming distribution system management device to respectively manage two transformers, then the code of the first outgoing distribution system management device is 0, the code of the second outgoing distribution system management device is 1, and so on.
The ID of the extended frame of CAN is used to transmit the electrical hierarchy coding of the device. The extended frame ID has 29 bits, and this 29 bits needs to be functionally divided reasonably and the coded information of the power distribution system management device is encapsulated, as shown in fig. 6 as encapsulation logic.
Specifically, the most significant bit 28 indicates whether the message has a super priority, and the higher the minimum priority of the preemptive ID is due to the communication mechanism of the CAN bus. Thus, the 28 th bit of the regular message is defined as "1", and if there is a particularly urgent message to be sent in preference to the regular message, the 28 th bit is defined as "0". Bits 27-20 of the ID are the meaning of the function code representing the message, and the function code length is 8 bytes, so that 256 message function allocations can be accommodated. Bits 19-16 of the ID indicate the voltage class at which the sender of the message is located, and 4 bytes in length can accommodate 16 voltage classes. The 15 th to 12 th bits of ID indicate the type of the power distribution cabinet where the sender of the message is located, and the length of 4 bytes can accommodate 16 different cabinet types. The 11 th to 6 th bits of ID represent the equipment number of the upper-level power distribution cabinet of the sender of the message, and the length of 6 bytes can accommodate 64 different numbers. Bits 5-0 of the ID represent the power distribution system management device number of the sender of the message, and the length of 6 bytes can accommodate 64 different numbers.
Because of the characteristic of CAN bus communication, each distribution system management device CAN initiate communication to the bus at any time and all devices on the bus CAN receive data sent by any one device, so that all cabinet distribution system management devices in one set of distribution system CAN acquire data of other distribution system management devices at will, and the technical support for data synchronization is provided for overload automatic breaking and short-circuit protection functions.
Example 3:
the present embodiment is based on a specific application scenario of a power distribution system management device provided in embodiment 1 and a power distribution system management method provided in embodiment 2, and the following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are not used to limit the protection scope of the present invention.
As shown in fig. 7, if the conventional molded case switch of the circuit breaker or the outlet cabinet is used for overload protection, the following situations may occur:
first scenario: assuming that the #1-1-2 cabinet in the figure is overloaded and causes the #1-1 cabinet to also be overloaded, then the following three cases occur back in certain circumstances:
1. #1-1 tripped before #1-1-2,
2.#1-1 trips simultaneously with #1-1-2,
3.#1-1-2 tripped prior to # 1-1.
For the 3 rd case we are most willing to see, because the outlet cabinet trips in time, thus avoiding the incoming main cabinet trip to cause #1-1-1 to also power down. However, the 1 st and 2 nd cases often occur due to various factors, and particularly, when the first case occurs, the service personnel have no head at all, which branch causes the incoming cabinet to trip.
Second scenario: if neither of the cabinets #1-2-1 and #1-2-2 is overloaded as shown in fig. 7, however, the addition of the loads of both causes overload of # 1-2. Under certain conditions, the circuit breaker in the #1-2 cabinet will perform a protection action, resulting in a power outage for both the #1-2-1 and #1-2-2 cabinets. It is also unclear to the service personnel what causes the trip to occur for this situation, and the appearance of this situation can confuse the service personnel.
In the power distribution structure shown in fig. 7, if conventional line short-circuit protection is adopted, it is difficult to determine the specific position where the short-circuit occurs. Assuming that the distribution system under the #1-1-2 cabinet flags is shorted, so that the #1-1-2, #1-1 and G4 cabinets sense the short circuit condition, several conditions are generated:
1, tripping the G4 cabinet, and keeping the rest of the cabinet without action;
#1-1 tripped, rest not actuated;
#1-1-2 tripped, the rest not actuated;
#1-1-2 with #1-1 action, G4 not action;
#1-1 with G4 action, #1-1-2 not action;
g4, #1-1, #1-1-2 all operate.
For the 1 st situation, the maintainer can only know that the quick break protection occurs from the fault alarm record on the microcomputer protection on the G4 cabinet, but in particular, the following line is unknown, so that a short circuit point can occur at the voltage transformation 1, possibly at the connection position of the #1-1 and the G4, and possibly at the power distribution system under the #1-1-1 flag. Because of the great possibility, the traditional short-circuit protection mode and the traditional overhaul method need to check each place where faults possibly occur so as to fully eliminate the faults. Such a removal method is very inefficient and fails to locate the failure point in time resulting in a longer outage time leading to greater economic losses.
As shown in fig. 3, if the power distribution system management device and the method provided by the invention are adopted to perform overload protection, the power distribution system management device installed in #1-1 will firstly obtain the electrical signal of the rogowski coil from the circuit breaker, and the current value passing through the rogowski coil at present, namely the three-phase current value and the zero sequence current value passing through the #1-1 cabinet at present, is obtained through signal processing and calculation. The power distribution system management device simultaneously takes over the trip action signal of the circuit breaker. The power distribution system management devices installed in #1-1-1 and #1-1-2 can acquire the three-phase current and the zero-sequence current of the current cabinet through the corresponding current transformers. The power distribution system management device #1-1 monitors the current data at any time, and in this embodiment, the refresh period is set to 20ms, and the current and time setting values of overload long delay are preset in the power distribution system management device. The current value collected by the power distribution system management device and the overload long-delay current setting value, the overload long-delay time setting value and the tripping time of the intelligent circuit breaker meet the following relations:
wherein: i represents the maximum value of ABC three-phase instantaneous current values collected by a power distribution system management device, I represents an overload long-delay current setting value, T represents an overload long-delay time setting value, and T represents the tripping time of a circuit breaker. Assuming that the current of the current A, B, C three phases is 10A, 12A and 15A respectively, i.e. i=15a, a current setting value i=10a is set, and an overload long delay time setting value t=100 seconds is set, then the tripping time is calculated to be t=100 seconds, so that if the current is not changed, the power distribution system management device controls the circuit breaker to break the disconnecting link lower cabinet #1-1-1 and #1-1-2 to cut power. Rules can be formulated: the low-voltage main cabinet power distribution system management device notifies the feeder cabinet power distribution system management device under the flag to divide the breaker when approaching to tripping. For example, when the timer trip time is less than a preset time: and 5 seconds, starting the linkage protection logic. And notifying the corresponding power distribution system management devices to execute the breaker dividing operation one by one according to the priority of the lower power distribution cabinet until the current detected by the #1-1 power distribution system management device is lower than the overload long-delay current setting value.
Specifically, the linkage protection logic is: the #1-1 power distribution system management device firstly detects whether the #1-1-1 power distribution system management device is on-line or not, the breaker is in a 'closed' state, the linkage protection function is already on, if one of the #1-1-1 power distribution system management device and the #1-1-1 power distribution system management device is not met, the #1-1-1 power distribution system management device continues to judge the #1-1-2 power distribution system management device, if the #1-1-1 power distribution system management device meets the condition, a tripping signal is sent to the #1-1-1 power distribution system management device through the CAN bus, and the #1-1 power distribution system management device immediately executes the breaker operation after receiving the signal. If the current detected by #1-1-1 after the #1-1-1 is disconnected having fallen below the setting value i indicates that the protection function is functioning the effect-the tripping of the breaker of the cabinet #1-1-1 is controlled to avoid the tripping of the cabinet #1-1 to cause a power failure in a larger range. If #1-1 detects that the current is still greater than the setting value i, the control of cutting #1-1-2 is continued, or if the timer exceeds T, the #1-1 power distribution system management device controls the circuit breaker of #1-1 to trip (basically, the situation is caused by CAN communication failure or unreasonable priority configuration).
In actual operation, the user needs to configure the priority of the feeder distribution system management device according to the needs of the user. When a user considers that the power supply of a certain feeder cabinet is least important (such as an office lighting circuit), the intelligent breaking priority of the power distribution system management device of the cabinet is set to be the highest. When the distribution system management device of the incoming line cabinet monitors that the overload intelligent breaking condition is met currently, the distribution system management device with the highest priority is firstly informed to execute tripping operation, so that the total load of the total cabinet is reduced, and the important line is ensured not to be powered off.
If the power distribution system management device and the method provided by the invention are used for short-circuit protection, the power distribution system management device on each power distribution cabinet is firstly set to sample voltage and current data at the same sampling frequency and at the same time by adopting the same method. Specifically, the sampled voltage and current data is sampled at a frequency of 64 points per cycle by a high-speed AD unit inside STM32F407, and FFT (fast fourier transform) is performed for 64 points per sample to obtain the real part and imaginary part of the fundamental wave, and the amplitude and phase of the fundamental wave can be obtained by further calculation. Therefore, the distribution system management device can recognize the electrical quantity change of about 20ms at the highest. The distribution system management device is arranged to record the electric quantity change value of about 1 second every 20ms cycle, namely all electric quantity instantaneous values (comprising three-phase voltage and three-phase current plus zero sequence current) of the past 50 times are cached.
As shown in fig. 4, the power distribution system management device determines whether the electrical data in the current circuit satisfies the quick-break trip condition: if the quick break tripping condition is met, an instruction is issued to a lower-level power distribution system management device: freezing and caching the electrical data, uploading the frozen and cached electrical data to a power distribution system server, and executing tripping operation; after the cutting-off is finished, the power distribution system management device performs fault information input and wave recording, and the fault information is uploaded to a power distribution system server; if the quick breaking tripping condition is not met but an instruction for freezing and caching the electrical data sent by the upper-level power distribution system management device is received, the cached electrical data is frozen and uploaded to a power distribution system server; and if the quick-break tripping condition is not met and the instruction for freezing the cache data is not received, continuing to circularly store the subsequent electrical data.
As shown in fig. 8, the power distribution system server constantly monitors the power distribution system management device for information on the quick disconnect. If the power distribution system management device reports the information of 'quick break protection', the reported power distribution system management device level is judged first. If the power distribution system management device of the 380V feeder cabinet reports, the short circuit fault is indicated to be positioned directly, so that the power distribution system server only needs to acquire the reported information of the power distribution system management device of the feeder cabinet, and the position of the fault point of the user can be informed. If the data is reported by the 380V incoming line distribution system management device, the cache data of all feeder cabinet distribution system management devices at the lower stage of the incoming line distribution system management device are required to be extracted, and the corresponding maximum value is required to be extracted. The power distribution system server calculates the maximum current value I in the cache data max Comparing with the quick-break value Id set by the corresponding distribution system management device, if I max If the power distribution system management device is larger than Id, the power distribution system management device and the lower-level power distribution system management device are determined to have short circuit faults. If I max If the Id is smaller than the Id, the power distribution system management device does not generate short-circuit fault, if a 380V incoming line is matchedAnd if the buffer data provided by all lower feeder cabinet distribution system management devices of the electric system management device show that the short circuit fault does not exist, judging that the fault occurs at the cable connection position. And the fault occurrence position can be positioned by recursion layer by layer from the power distribution system management device with quick break.
Figure 9 shows data frozen by a 380V low voltage feeder cabinet distribution system management device. The data span is from 0 th second to 0.98 th second for a total of 50 sets of data, with 0.02 second intervals between each set of data. From the frozen data, it can be determined that the three-phase voltage (U a ，U b ，U c ) Are 220V, three-phase current (I a ，I b ，I c ) Both 5A. When the three phases are suddenly short-circuited, the current value is suddenly changed to be more than 100A, the voltage is also reduced to 130V-150V, and then the quick-break protection of the upper low-voltage incoming line cabinet is triggered, so that the cabinet is powered off, the voltage is further reduced to 0V, and the short-circuit current is also randomly disappeared. As shown in the visual chart of fig. 10, it can be determined from the frozen data that the short circuit occurred at 0.9s and the protection occurred at 0.92 s.
In order to realize data synchronization among the distribution system management devices, a model for mutual communication of the distribution system management devices in the distribution system needs to be established, codes are configured for each distribution system management device, and data intercommunication of the distribution system management devices is realized by making a transmission protocol through a CAN bus.
As shown in fig. 5, it is assumed that a distribution room is constructed with a 10kv voltage inlet and a 10kv outlet, and then a transformer is connected to each of them to change the voltage to 380 v. Then the back of the first transformer is connected with two low-voltage inlet wires, and the back of the two low-voltage inlet wire cabinets is respectively connected with two low-voltage outlet wires. The second transformer is connected with one voltage incoming line and then two low-voltage outgoing lines. Each device is encoded by adopting the encoding mode of the invention: the voltage level of the 10KV high-voltage isolation cabinet power distribution system management device is 10Kv, so that the first number is 3, then the second number is 6 according to the cabinet type, the upper-level number can adopt a default value of 0, and the device is the first equipment of the type of the level, so that the fourth number is 0. And so on all power distribution system management device codes can be determined. A complete power distribution system management device code is shown in fig. 11.
Because of the characteristic of CAN bus communication, each distribution system management device CAN initiate communication to the bus at any time and all devices on the bus CAN receive data sent by any one device, so that all cabinet distribution system management devices in one set of distribution system CAN acquire data of other distribution system management devices at will, and the technical support for data synchronization is provided for overload automatic breaking and short-circuit protection functions.
The foregoing is merely a preferred embodiment of the present invention, and it should be noted that modifications and variations could be made by those skilled in the art without departing from the technical principles of the present invention, and such modifications and variations should also be regarded as being within the scope of the invention.

Claims (3)

1. The power distribution system management method is characterized in that a data model of mutual communication of power distribution system management devices in a power distribution system is established, electric hierarchy codes are configured for each device of the power distribution system, the code information is packaged into an ID of a CAN (controller area network) extension frame, and data of the power distribution system management devices are transmitted through a data frame carrier, so that data sharing and distribution among the power distribution system management devices are realized; wherein, the coding rule of the electrical level coding is: defining a first number to represent a management voltage level of a current power distribution system management device, 1 to represent a 380 volt power distribution system, 2 to represent a 6 kv power distribution system, 3 to represent a 10kv power distribution system, and 4 to represent a 35 kv power distribution system; defining a second digit to represent the type of a cabinet where a current power distribution system management device is located, classifying the cabinet into 7 types, wherein 0 represents an incoming cabinet, 1 represents an outgoing cabinet, 2 represents a contact cabinet, 3 represents a capacitor cabinet, 4 represents a power generation cabinet, 5 represents a transformer cabinet and 6 represents an isolation cabinet; defining a third number to represent a superior number of the power distribution system management device; the fourth number represents its own code; the codes of the latter two numbers refer to the numbers of a plurality of power distribution system management devices under the same condition; the ID of the CAN extension frame has 29 bits, the 29 bits are reasonably functionally divided, the coding information of the power distribution system management device is packaged, and the 28 th bit of the highest bit indicates whether the message has super priority or not; bits 27-20 are the meaning of the functional code representing the message, and the length of the functional code is 8 bytes to accommodate 256 message functional allocations; bits 19-16 represent the voltage class at which the sender of the message is located, with 4 bytes in length accommodating 16 voltage classes; bits 15-12 represent the type of the power distribution cabinet where the sender of the message is located, and 4 bytes in length accommodate 16 different cabinet types; bits 11-6 represent the equipment number of the upper-level power distribution cabinet of the message sender, and the length of 6 bytes accommodates 64 different numbers; bits 5-0 represent the power distribution system management device number of the message sender, and the length of 6 bytes accommodates 64 different numbers;
the method is realized by adopting any one of the following methods:
method a: the power distribution system management device acquires three-phase current values, and judges whether overload linkage protection is started or not according to the maximum current value; comprising the following steps:
the power distribution system management device obtains three-phase current values, finds a maximum current value I, and judges the magnitudes of the maximum current value I and an overload long-delay current setting value I:
if I is more than or equal to I, the power distribution system management device starts a timer function to count time, calculates tripping time T, and compares whether the difference value between the current timer value and the current timer value is smaller than a set threshold value; if the difference value is smaller than the set threshold value, starting linkage protection logic; if the difference value is greater than or equal to the set threshold value, continuously acquiring a three-phase current value;
if I is less than I, closing the function emptying time of the timer, and continuously obtaining a three-phase current value;
method b: the power distribution system management device caches the electrical data, and judges whether to freeze the cached data and whether to start quick-break tripping protection according to the electrical data in the current circuit; comprising the following steps:
the power distribution system management device caches the electrical data and judges whether the current electrical quantity meets the quick-break tripping condition or not:
if the quick-break tripping condition is met, notifying a lower-level power distribution system management device to freeze the cached electric data and uploading the frozen cached electric data to a power distribution system server, and executing tripping operation; after the cutting-off is finished, the power distribution system management device performs fault information input and wave recording, and the fault information is uploaded to a power distribution system server;
if the quick breaking tripping condition is not met but an instruction for freezing and caching the electrical data sent by the upper-level power distribution system management device is received, the electrical data are frozen and cached, and the frozen and cached electrical data are uploaded to a power distribution system server;
and if the quick-break tripping condition is not met and the instruction for freezing the cache data is not received, continuing to circularly store the subsequent electrical data.
2. The power distribution system management method according to claim 1, wherein the calculation formula for calculating the trip time T is:
wherein ,Irepresenting the maximum value of three-phase instantaneous current values collected by a power distribution system management device, i representing an overload long-delay current setting value, t representing an overload long-delay time setting value,Tindicating the trip time of the circuit breaker.
3. The method of claim 1, wherein the coordinated protection logic comprises sequentially issuing trip instructions according to a priority of a lower power distribution cabinet set by a user, and wherein the total load of the total cabinet of the power distribution cabinet is reduced until it is ensured that the important line is not powered off.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105449865A (en) * 2015-12-17 2016-03-30 南京因泰莱电器股份有限公司 Intelligent (feeder terminal unit) FTU used for fault positioning and isolating for distribution network
CN105743082A (en) * 2016-04-27 2016-07-06 武汉大学 Overload switching device suitable for DC power distribution system
CN110412416A (en) * 2019-07-04 2019-11-05 天津市中力神盾电子科技有限公司 Distribution line fault recording method and system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105449865A (en) * 2015-12-17 2016-03-30 南京因泰莱电器股份有限公司 Intelligent (feeder terminal unit) FTU used for fault positioning and isolating for distribution network
CN105743082A (en) * 2016-04-27 2016-07-06 武汉大学 Overload switching device suitable for DC power distribution system
CN110412416A (en) * 2019-07-04 2019-11-05 天津市中力神盾电子科技有限公司 Distribution line fault recording method and system

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