255results about How to "Reduce the scope of outages" patented technology

The invention provides a real-time data collecting and fault positioning system of a power distribution network and a working method thereof. The real-time data collecting and fault positioning system comprises transformer substation voltage collecting units, a plurality of line units, a real-time data server, a background monitoring computer and a handheld terminal, wherein each transformer substation is provided with one transformer substation voltage collecting unit; each transformer substation voltage collecting unit comprises one intelligent voltage detection terminal; each line unit comprises three fault positioning and data collecting sensors and one communication and calculation terminal; the intelligent voltage detection terminal, the communication and calculation terminal and the handheld terminal are in wireless communication with the real-time data server; the three fault positioning and data collecting sensors of the same line unit are in short-distance wireless communication with the communication and calculation terminal. The working method mainly comprises the step of carrying out real-time data collection and fault judgment. The information precision of power transmission line data which is collected in real time is high, short circuit and grounding faults are rapidly and accurately judged, the time of powering off and overhauling is shortened, the quantity of fault line patrolling workers is reduced and manpower and material resources are saved.

The invention discloses a power distribution network broken line fault location method. According to a structure of a power distribution network and a power supply mode, a local power distribution network line section is divided into a plurality of kinds of typical sections, and characteristics of voltage and load flow of each of endpoints of the typical sections in different broken line faults are proposed. During application, the characteristics of each local line section of the power distribution network are matched with the typical sections, types of the typical sections which the each local line section belongs to are determined, the measured characteristics of the voltage and the load flow of each of the endpoints in the each local line section are matched with the characteristics of the voltage and the load flow of each of the endpoints of the typical sections in the different broken line faults to judge whether the line section has the broken line fault and to judge types of the broken line faults, and the typical sections correspond to the line section. According to the power distribution network broken line fault location method, a modeling rule is used for customizing the method, and the comprehensiveness and the reliability for problem processing are achieved; the customization of the rule is flexible and prone to adapt to a plurality of operating modes of the power distribution network; the location is accurate, and the fault location of sections can be achieved; and human line patrolling is avoided, and the power distribution network broken line fault location method is an ideal method.

The invention discloses a section power supply and status measurement and control method of parallel-connected traction networks at the tail end of a double track railway. By taking the section (10km) of the railway as a unit, a contact line sectioning and a sub-section post are additionally arranged at a section boundary. The sub-section post comprises a circuit breaker, a current transformer, a voltage transformer and a measurement and control unit. The circuit breaker and the current transformer connected with the circuit breaker in series are in bridge connection with the two ends of the contact line sectioning, and the sectioning is series-connected in the contact line. Through the arrangement of the sectioning and the sub-section post and the introduction of running status criterion, the running situation of charging trains on the traction networks can be timely and accurately mastered by operators on duty in a traction substation or dispatching room; by using the fault criterion, various faults can be timely and accurately found, distinguished and isolated, the continuous power supply and running of fault-free sections are ensured, the power outage scope is reduced to the maximum extent, and further the reliability of power supply of the traction networks is improved. The device has less investment and is easy to implement, not only is conveniently used by a new line, but also facilitates the transformation of an existing line.

The invention discloses a self-healing control method of a distribution network, which adopts centralization coordination and the distribution coordination, has self-adaptability during signal treatment and generation of a control strategy, and can automatically complete the control process without manual intervention to coordinate actions of a relay protection device and a protection control device, actions of a switch and a smart switch and the action of a safety automatic device. The method comprises a distributed self-healing control step and a centralized self-healing control step, can determine the current operation state of the distribution network by collecting the voltage data, the current data, the on-off state and the like, and can apply an intelligent method to make a decisionso as to coordinated control the switch, the protection control device, the safety automatic device and the like, thereby enabling the distribution network to always transfer to a more healthy state,improving the safety, the reliability, the quality and the economy of the distribution network and enhancing the emergency capacity.

A method and a device for quickly locating faults of an overhead line on the basis of time synchronization belong to the technical field of intelligent grid distribution automation. The method for quickly locating the faults of the overhead line on the basis of time synchronization comprises a distribution overhead line and a master station and is characterized in that a plurality of distribution data collection units arranged on the distribution overhead line collect voltage signals of the distribution overhead line and current signals of each branch through the time synchronization technology, collected data with time labels are transmitted back to the master station to achieve calculation and judgment on the branch where the faults happen, and position information of a fault interval and the fault state of a line are displayed. The device consists of the distribution data collection units, a time reference unit, a communication system and a master station system. By utilizing the method, the device can automatically judge a fault section of a power supply line, provide the position information of the fault interval, especially improve accuracy of single-phase grounding fault judgement, replace with small current grounding routing system of a transformer station, reduce a power failure range, shorten line reparation time, and improve power supply reliability of a power supply system.

The invention, which belongs to the technical field of automation of the distribution network, relates to an intelligent protection system of distribution network. According to the invention, the system comprises at least two section switches installed at a distribution line and matched intelligent protection terminals, a communication system and a distribution network automation system platform. According to the system, non-level different current protection is used; and thus the current protection tripping time setting values of all section switches are identical. The intelligent protection terminals identify the supervisor-subordinate relation of all intelligent protection terminals according to a network topological relation file. When a fault occurs at the distribution line, tripping of the corresponding section switch is carried out, the faulty line section is isolated, and the non-fault line section carries out operation continuously; and power supplying of the non-fault section behind the fault point is recovered by a connecting switch of another distribution line. Therefore, the line fault power-failure range can be reduced; power supply reliability of the distribution network is improved; and secure operation of the power system is guaranteed.

The invention relates to a method for positioning a short-circuit fault of a distribution network based on distributed intelligent multi-calibration. The method comprises the following steps of: arranging a plurality of intelligent agents in the distribution network and establishing a modeled multilevel multi-verification short-circuit fault positioning rule for different operating modes of the distribution network; in the operation process of the distribution network, monitoring operation information of a local current distribution network in real time through each distributed intelligent agent; once the current is out of limit, sending a current out-of-limit signal to the directly-adjacent intelligent agent and a superior intelligent agent and checking whether a short-circuit fault early-warning signal exists locally; if so, assuring that the short-circuit fault happens locally; otherwise, waiting for receiving the current out-of-limit signal sent by the directly-adjacent intelligent agent; and after delaying the signal for time t, according to the local current out-of-limit signal and the received current out-of-limit signal, carrying out rule matching and multi-condition calibration to determine a fault diagnosis result by utilizing a local short-circuit fault positioning rule library and combining a wiring type of the distribution network and the position of the intelligent agent.

The invention relates to an adaptive cascade direction interlocking relaying method based on GOOSE (Generic Object Oriented Substation Event), which comprises the following steps: 1) initial interlocking directions of protective relays are set according to an initial interlocking direction tuning rule; 2) a directional element judges the direction of a current fault current which is compared with the initial interlocking directions by a direction comparator to judge whether the directions of two parts are the same, if yes, the step 3) is carried out, if not, IN2 is gated, and a interlocking signal is output to OUT2; 3) the direction comparator gates IN1, and outputs the interlocking signal to the OUT1 and the direction of the output signal is opposite from the initial interlocking direction at this time; 4) a receiving virtual terminal judges whether the interlocking signal is received, if yes, the interlocking is carried, if not, the step 5) is carried out; and 5) an over-current element judges whether the current fault current exceeds a local over-current protection starting fixed value, if yes, a trip signal is sent. In comparison with the prior art, the method has the advantages that the safe and reliable operation of a system is ensured and applicability is good.

Provided is a fault identification and protection method of an electrified railway AT traction network. When network voltage is lower than a specified value, labeling no-load trend symbol values of the near ends and the far ends of a touch net T and a negative feeder F in each self-coupling segment with 0, labeling influent trend symbol values with 1, labeling effluent trend symbol values with -1, if an absolute value of a sum of the trend symbol values of two ends of the touch net T in each self-coupling segment is larger than or equal to 1, or a failure absolute value of a sum of the trend symbol values of two ends of the negative feeder F is larger than or equal to 1, or a failure absolute value of a sum of the trend symbol values of two ends of a touch net T branch and a negative feeder F branch is larger than or equal to 1, respectively judging the touch net T to be in short circuit failure to the ground, or the negative feeder F to be in short circuit failure to the ground, or the touch net T to be in short circuit failure to the negative feeder F, and breaking off all breakers at two ends of each self-coupling segment. Short-circuit reactance calculated according to corresponding voltage and short-circuit current at two ends of each self-coupling segment and the corresponding length of the self-coupling segment determine failure positions.

A method and apparatus for locating and isoalting the failure in distributing circuit is disclosed. Said apparatus is used in conjunction with vacuum switch, power supply, and failure segment indicator to form a core unit of an automatic distributing network system. The said method can quickly locate and automatically isolate the failure region for increasing reliability of power supply by distribution system.

Disclosed is a power distribution network fault handling method based on self-recovering control. By a centralized and distributed coordination power distribution network fault self-recovering control method, signal processing and control strategy generation are adaptive, the control process is automatically completed without manual intervention, and behaviors of a relay protection device and a protection control device, a switch and an intelligent switch, and an automatic safety device are coordinated. The power distribution network fault handling method includes the steps of automatic detection of power distribution network faults, distributed self-recovering control and centralized self-recovering control.

The invention relates to a single-phase earth fault direction judgment and processing method of a small current grounding system. In terms of a fault direction judgment method, the session which a single-phase fault point belongs to on a main line is judged according to zero-sequence currents, zero-sequence voltage and the included angle relation between the zero-sequence currents and the zero-sequence voltage tested through a section switch on the main line where a single-phase earth fault occurs, the fault session is isolated according to the judgment result, and normal power supply of a non-fault session line is guaranteed to the largest extent. According to the judgment and processing method, the single-phase earth fault session of the main line can be automatically isolated, and power supply reliability of a power distribution network is improved; additionally, according to the single-phase grounding direction judgment method, a main line boundary function is embedded in the section switch of a 10kV feeder line, the range in power failure caused by the single-phase earth fault can be shortened to the largest extent, and accordingly reliability and safety of power supply are improved.

The invention discloses a segmenting power supply distributed protection system for an electrified railway traction network. An overhead line in the electrified railway traction network is divided into a plurality of sections by corresponding to the intervals of a railway, sectionalizers and switching stations are additionally arranged on segmentation positions; each switching station comprises a breaker, a current transformer, a voltage transformer and a measurement and control unit; the breaker is always under a switching-on state; the secondary side of the voltage transformer and the secondary side of the current transformer of the switching station, the secondary side of the current transformer of the left adjacent switching station and the secondary side of the current transformer of the right adjacent switching station are connected with the input end of each measurement and control unit; the output end of each measurement and control unit is connected with the control end of the breaker of each switching station; each measurement and control unit is connected with a traction substation or control center via a transmission network. The invention forms a segmenting distributed protection method for the traction network. Compared with a centralized protection method, the segmenting distributed protection method has the characteristics that the instantaneity is not affected by the segmentation amount of the traction network. The relevant device disclosed by the invention has the advantages of small investment, convenience in implementation and convenience in new line adoption and old line modification.

The invention introduces a feeder fault handling method, which comprises the following steps of: 1) conducting online search and locating a feeder fault; 2) conducting network topology analysis to draw a conclusion; 3) finding out the section of the fault; 4) searching for the boundary switch of the fault section and making a fault isolation plan; 5) defining non-fault power outage areas; 6) making power supply restoration plans for outage areas on the upstream side and the downstream side of the fault; 7) conducting safety evaluation to the downstream power supply restoration plan; and 8) executing the plans according to the safety evaluation obtained at the step 7. The feeder fault handling method has the advantages that: 1) the method is suitable for the automatic construction of feeders of a power distribution network which is wired in any way; 2) the practicability is high, the impedance parameters of the equipment of the distribution network are not required and the power flow calculation module is not required to be called; and 3) the power supply restoration can be separately conducted to the non-fault sections, so as to reduce the power outage range and decrease the poweroutage duration as much as possible.

The invention discloses an on-site crane car for power transformation engineering, which comprises a base, a lifting and hanging rod mounted on the base through a rotating mechanism, an elevation angle regulating mechanism arranged at the lower part of the lifting and hanging rod, and a suspension rope hanging adapter arranged at the top end of the lifting and hanging rod through a forcipated support, wherein the lifting and hanging rod is connected with the rotating mechanism through a hinged support and the base is provided with travel wheels. The crane car is particularly suitable for on-site uninstallation and installation of equipment in power transformation engineering. The crane car has a small size and a light weight, occupies less space, better solves the problem that the large-size lifting device can not be used in a transformer station in certain cases, eliminates the limitation of on-site spatial position and peripheral electrified equipment on lifting operation, and can greatly reduce the labor intensity of operating staff, reduce the power failure range during the equipment lifting process and increase the operating efficiency and the operation safety coefficient. Besides, the crane car has the advantages of being convenient for folding, transport and storage, easy to operate and convenient to use.

The invention provides a direct current micro grid topology design method based on DC-DC (Direct Current-Direct Current) sectionalizers and belongs to the technical field of micro grid. In an annular direct current micro grid topology, a plurality of direct current micro grid sectionalizers based on high frequency isolation DC / DC conversion (short for DC-DC sectionalizers) are arranged for replacing solid circuit breakers. A direct current micro grid wire frame is of an annular structure, and an annular busbar is divided into a plurality of segments and a plurality of voltage levels. Adjacent busbar segments are connected through the DC-DC sectionalizers or circuit breakers so as to form a power supply layout with multiple segmentations and multiple connections. The DC-DC sectionalizers are of a dual full bridge topology structure, and are subjected to alternating current coupling through high-frequency transformers. The direct current micro grid topology design method has the advantages that on the aspects such as electric isolation, power flow control and connection among busbars with different voltage levels, the method has obvious superiority, the response speed is rapid and the sensitivity is high. When a direct current busbar or device has a fault, the DC-DC sectionalizers are not affected by capacitance instantaneous discharge, the faulted busbar is isolated, the power failure range is reduced as far as possible, and the reliability of the system is improved.

The invention provides a method for generating a fault recovery scheme for load transfer when multiple buses are in loss of voltage. An external interconnection power supply is fully utilized. When the multiple buses are in loss of voltage, a buscouple power supply and the external interconnection power supply are matched for load transfer, in other words, loads of power-loss feeder lines without the external interconnection power supply are supplied by an instation reserve bus in a transfer mode, loads which cannot be supplied in a transfer mode have to lose power, and power supply of important loads is guaranteed in a priority mode; feeder lines with the external interconnection power supply are wholly supplied by an interconnection power supply outside a station in a transfer mode, and specifically a multi-fault power supply recovery method is adopted. Buscouple reserve capacity and the external interconnection power supply can be fully utilized, power-loss loads are recovered to the maximum degree, and the device utilization rate of a main transformer is increased.

The invention discloses an automatic electric pole climbing mechanism. The mechanism comprises an upper hoop, a lower hoop, a workbench, a connection post cylinder and a hydraulic station; the upper hoop and the lower hoop are the same in structure and each comprises a left hoop half and a right hoop half for encircling an electric pole, and the connection end of each left hoop half and the corresponding right hoop half is provided with a first extending-and-contracting oil cylinder which controls the corresponding left hoop half and the corresponding right hoop half to be unfolded and folded; the workbench is connected to the outer side of the first extending-and-contracting oil cylinder of the upper hoop and sequentially connected with a first operating oil cylinder, a second operating oil cylinder and a third operating oil cylinder from one side which is close to the corresponding first extending-and-contracting oil cylinder to the outside, wherein the top of the first operating oil cylinder, the top of the second operating oil cylinder and the top of the third operating oil cylinder are each provided with an insertion hole for allowing an operating instrument to be hung therein and a fixing lock; the connection post cylinder is vertically connected to the outer sides of the first extending-and-contracting oil cylinder of the upper hoop and the first extending-and-contracting oil cylinder of the lower hoop. By means of the automatic electric pole climbing mechanism, an operator can perform work of live part verification and ground lead hanging on a three-phase wire on the electric pole by conducting operation on the ground, meanwhile, an operating device can be dismounted, the links that a worker climbs the pole and performs the live part verification within a close range are omitted, and operating risks of the worker are greatly lowered.

The invention relates to an OMS equipment transaction management and control information system supported by a GID platform. The OMS equipment transaction management and control information system at least comprises one information interaction bus module and one OMS on-line transaction audit and circulation module. Aiming to lower the distribution network personal safety risk and improve power supply reliability, depending on a power distribution automatic system intelligent platform, and using a normalized equipment transaction management system as a technical means, the OMS equipment transaction management and control information system realizes organic combination of a production safety management system (PMS), a distribution network geographic information system (GIS) and an integrated control management system (OMS) production management system.

The invention discloses a high-speed railway supply arm shunt tripping protection method based on impedance characteristics. The method is realized through impedance protection elements distributed in a substation, an AT station and a subarea station in a scattered mode and through a communication network, wherein the quadrangular operation characteristics are adopted for the impedance protection elements. Each impedance protection element can transmit shunt tripping instructions to other impedance protection elements or receive the shunt tripping instructions from other impedance protection elements on the same supply arm through the communication network to rapidly isolate a fault supply arm. The impedance protection elements of the substation and the impedance protection elements of the AT station jointly protect all power supply sections between the substation and the AT station. The impedance protection elements of the AT station and the impedance protection elements of the subarea station jointly protect all power supply sections between the AT station and the subarea station. When a fault of any impedance protection element is detected, a breaker of the fault supply arm in the station is tripped off, a shunt tripping instruction is transmitted to the other impedance protection elements on the same supply arm, the other impedance protection elements receive the shunt tripping instruction and then trip off the corresponding breakers, and consequently the fault supply arm is rapidly isolated, and power supply of the other supply arm which is connected with the fault supply arm in parallel can not be influenced.

The invention relates to a transmission grid fault detection system and method based on an internet of thing technology. The method is characterized by: monitoring online and in real time whether changes of the voltage and current of a high-voltage transmission line three-phase fixed point are balanced by utilizing a three-phase zero sequence voltage and a current balance measurement method; and judging whether the fixed point of a high-voltage overhead line is abnormal based on the change features of the voltage and the current under various conditions. The system comprises grounding, open circuit and short circuit fault diagnoses. The system and method of the invention enable fault monitoring level to be improved, wherein the short circuit fault alarm accuracy can reach more than 98.5%, and the grounding fault alarm accuracy can reach more than 97%. A detection device possesses a self-learning function, namely, a plurality of threshold values do not need to be set according to the transmission lines with different loads, so that the workload before putting the detection device into use is reduced, the universality is improved, the power cut range is reduced, the power cut time is shortened, and the power supply reliability is improved substantially.

The invention discloses a main electrical connection of a double-bus disconnecting link section. The main electrical connection of the double-bus disconnecting link section at least comprises a double bus, outgoing breakers, a bus tie breaker, outgoing disconnecting switches, section disconnecting switches, bus tie disconnecting switches and bus facilities, wherein the double bus consists of two sections of buses; middles of the two sections of buses of the double bus are respectively sectioned by adopting two section disconnecting switches; the double bus is only provided with the bus tie breaker and the corresponding bus tie disconnecting switches; and both sides of the section of each section disconnecting switch on the double bus are respectively provided with a set of bus facilities. When electrical equipment normally runs by adopting gas insulated switchgear (GIS), the running mode of the electrical equipment is same as that of a double-bus connection. When a section of bus is maintained or an outgoing interval is extended, by operating the section disconnecting switches of the bus, one of sectioned buses can be ensured to normally run, and therefore, the power cut range is reduced, and the power supply reliability is improved.

The present invention discloses an emergency load shedding control method based on trace sensitivity. The method comprises obtaining traces of post-accident state variables through power system transient numerical simulation, so as to solve transient security and stability allowance indicator vectors, and judging if solving emergency load shedding measures need to be carried out through transient security and stability constraint conditions; solving a trace sensitivity matrix of transient security and stability allowance indicators through power system transient numerical simulation and a numerical perturbation method, and linearizing the transient security and stability constraint conditions. The transient security and stability, including transient power angle stability, transient frequency security and transient voltage security of a post-accident system may be ensured, the load shedding cost is reduced, and economical efficiency of the measures is raised. Through trace sensitivity, the transient security and stability conditions are linearized, the original problem is converted into a linear programming problem, iteration solving is realized, and the rate of convergence is fast.

The invention discloses a reclosure method involving a distributed generation power distribution network based on wide area information. The reclosure method aims at achieving the technical purpose of guaranteeing the power supply reliability of loads. The reclosure method includes the following steps that directional elements, a circuit breaker and a protector are arranged, reclosure operational motion is set, whether a distributed generation has the isolated island operation capacity or not is judged, and protection and reclosure are conducted. Compared with the prior art, the problem of asynchronous reclosure caused by DG upstream protection maloperation generated by adjacent feeder line faults is solved, operation of switching DG control strategies and splitting an isolated island generated when a DG downstream line breaks down in a reclosure front acceleration protection action mode is avoided, DG control method switching and the action cooperative relationship between reclosure and protection are achieved by fully utilizing the wide area information, the reclosure method can be suitable for the power distribution network with DG access, the DG power supply capacity is brought into full play, the power failure range is reduced, the power failure time is shortened, and the power supply reliability of loads is guaranteed.

The invention relates to the technical field of power system distribution network single-phase ground fault detection, in particular to a distribution network line homonymous phase two-point successive ground fault line selection method. The distribution network line homonymous phase two-point successive ground fault line selection method comprises the specific steps of (1) real-time data acquisition, (2) fault starting discrimination, (3) characteristic component extraction, (4) characteristic component analytical processing, (5) single-point grounding discrimination, and (6) two-point grounding discrimination. After fault starting, zero-sequence current characteristic components of each line are extracted and analyzed, the characteristic component amplitude values are sorted by magnitude, and phase relations between the characteristic components of the lines at characteristic frequency are compared to find a grounding line. The distribution network line homonymous phase two-point successive ground fault line selection method effectively solves the distribution network line homonymous phase two-point ground fault line selection difficulty, is conductive to improving operation efficiency, reduces the power failure range, ensures the safe operation of the distribution network system and reduces personal injury and death.

The invention relates to a method for repairing indoor bus knife switch moving contact of high tension bus without power failure. The technical proposal includes following steps: breaking high-voltage circuit-breaker to be repaired, pulling bus knife switch, checking whether the moving and static contact is cut off or not and without foreign body; assembling electrification repair dielectric isolation baffle based on pulling bus knife switch moving, static contact surrounding electric equipment condition, shouldering assembled electrification repair dielectric isolation baffle with the insulating rod to put and pull between the moving, static contacts of the bus knife switch, after completely effective separating the electrification part, performing repair of the bus knife switch moving, static contacts; after work to be repaired is completed, withdrawing the electrification repair dielectric isolation baffle with the insulating rod and restoring electric transmission. The invention has beneficial effects of reducing power failure scope, making time of bus power failure processing failure decline, ensuring power supply reliability, improving work efficiency greatly and realizing quick response and operation.

The invention discloses an MMC converter DC power distribution network single-pole high-resistance grounding fault protection method, which mainly comprises the following steps of: judging whether a single-pole grounding fault occurs or not by taking the change rate of positive and negative pole voltages to ground of a DC power distribution network as a starting criterion and taking the voltage variation as a fault criterion; when a single-pole grounding fault occurs, firstly, determining a fault pole according to the magnitude of positive and negative pole voltages; preliminarily judging a fault line according to the magnitude and the direction of the fault electrode charging and discharging current detected at the head end of each line; and finally, injecting a detection signal into the fault electrode, and verifying the accuracy of the judgment according to the size of the detection signal detected at the head end of each line. When the two data are consistent, determining that the line is the fault line; and when the two data are inconsistent, re-determining the fault line by using the charging and discharging current criterion and the detection signal criterion and using a comprehensive weight method.

The invention discloses a fault traveling wave location method of multiple branch lines of a power distribution network. According to the method of the invention, traveling wave recording devices are installed at the head end of a trunk line, the tail end of the trunk line and the tail ends of the branch lines of a detected power distribution line; time for head-end reference traveling wave signals, tail-end reference traveling wave signals and fault traveling wave signals to arrive the head end of the trunk line, the tail end of the trunk line and the tail ends of the branch lines is acquired respectively through the traveling wave recording devices; based on a theory that traveling waves are transmitted according a shortest path of a line and traveling wave transmission characteristics in line faults, the branch lines are judged with different sequences according to a first condition formula and a second condition formula, and therefore, fault intervals of the multiple branch lines of the power distribution network can be determined fast and accurately; and calculation is carried out through a double-end traveling wave fault location formula, so that the positions of fault points of the lines can be located accurately. The method of the invention has the advantages of fast and accurate fault location and small calculation quantity, and can assist in shortening power outage time, decreasing a power outage range, and improving the power supply reliability of the power distribution network.

The invention discloses an automatic feeder protecting method for an overhead line four-section three-contact structure. When a trunk line of the overhead line four-section three-contact structure fails, a transformer substation outgoing breaker breaks, insulates failures and recloses after a distribution automation terminal determines a failure section. If the failures are permanent, subsection switches at the two ends of a feeder automation breakage failure section are started, a contact switch is closed, and non-failure section power is restored after tripping occurs again. When a branch line fails, after the distribution automation terminal determines a failure section, the transformer substation outgoing breaker and a failure section branch line breaker break and insulate failures, the transformer substation outing breaker recloses, and trunk line power supply is restored. The automatic feeder protecting method is high in power supply reliability, short in failure recovery time, small in power-off range, low in improvement, operation and maintenance cost, and suitable for areas which are provided with overhead lines and are high in reliability requirement.

The invention discloses an intelligent outdoor switch box and a closed-loop I-shaped power distribution network thereof. The intelligent outdoor switch box comprises an incoming wire PT and DTU interval, more than one circuit breaker interval and a bus PT interval; the PT and DTU interval comprises a centralized DTU and an incoming line voltage transformer which are electrically connected with each other; each circuit breaker interval is provided with a current transformer; the bus PT interval is provided with a voltage transformer; the centralized DTU is electrically connected with the current transformer of each circuit breaker interval; and the centralized DTU is electrically connected with the voltage transformer. According to the intelligent outdoor switch box and the closed-loop I-shaped power distribution network thereof of the invention, the centralized DTU is adopted; through an optical fiber differential protection function, a bus differential protection function, a backup protection function, an over-current quick-break protection function, a spare power automatic switching function and the like of the centralized DTU, information interaction between various switch boxesis realized in an optical fiber communication mode; and the quick fault isolation of a power distribution network line and the power restoration of a non-fault area are realized.