CN105375635A - Method and system of intelligent management of power distribution network cascading switching stations - Google Patents

Abstract

The invention discloses an intelligent management method and system for cascaded switching stations of a distribution network. The switching stations are all provided with fault handling terminals, each of which is connected to the optical fiber ring network through an Ethernet switch, and each of the fault processing terminals is provided with a communication server, and all of the communication servers Both are connected to the power distribution master station. The invention introduces the idea of line optical fiber differential protection and directional protection into the fault handling of distribution network, and forms an intelligent management system of distribution network cascaded switching stations according to the power supply relationship. The terminal uses the fast communication between the unit networks, only transmits the fault signal, and negotiates independently, which solves the selectivity of the protection action when the feeder is faulty, and realizes fault isolation at one time.

Description

Intelligent management method and system for distribution network cascaded switching stations

Technical field:

The invention relates to maintenance and management of a distribution network cascade switch station, in particular to an intelligent management method and system for a distribution network cascade switch station.

Background technique:

With the development of the national economy and the continuous improvement of people's material and cultural living standards, users have higher and higher requirements for power supply reliability. Power outages not only cause inconvenience to people's lives and bring great economic losses, but also have a great negative impact on society. Relevant studies have shown that every kilowatt-hour of power outage will bring an average economic loss of 40 yuan to users, and the economic loss caused by power outages in my country reaches hundreds of billions of yuan every year. Therefore, the power supply reliability of the distribution network needs to be improved urgently, and solving the fault handling problem of the distribution network is the key to improving the power supply reliability of the distribution network.

Zhengzhou is a pilot city for distribution automation of the State Grid Corporation of China. At present, a distribution automation system has been established in the Zhengdong New District and the High-tech Development Zone. The main station + DTU mode is adopted. The main station performs distribution network based on the real-time information of the equipment uploaded by the DTU. Running status analysis and monitoring. In this mode, when a fault occurs, the substation exit switch trips to remove the fault, and then uploads the information to the master station. After the master station judges the fault area, it performs remote closing and restores the power supply in the non-fault area. There are some problems in this fault handling mode. Some deficiencies were found during operation: the DTU does not have the protection trip function, and after a fault occurs, it leapfrogs to the substation to trip to expand the impact of the accident; the fault treatment is controlled at the main station, and the time for fault isolation and power supply restoration is relatively long, generally 20-30 seconds; communication The dependence is high, and fault isolation and power supply recovery are easily affected by the communication link.

Invention content:

The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide an intelligent management method and system for distribution network cascaded switching stations that are reasonable in design, simple and practical, quick to deal with faults, and reduce power outage time.

Technical scheme of the present invention is:

1. A method for intelligent management of distribution network cascaded switching stations, comprising the following steps:

a. An optical fiber ring network is formed between all switching stations, each of the switching stations is provided with a fault handling terminal, and each of the fault processing terminals is connected to the optical fiber ring network through an Ethernet switch, The fault handling terminals use the fast communication between the unit networks, only transmit the fault signal, negotiate independently, solve the selectivity of the protection action when the feeder is faulty, and realize fault isolation at one time;

b. With the help of line fiber optic channel, the sampling data is transmitted to the opposite side in real time, and the sampling data of the opposite side is accepted at the same time. The protection of each side uses the local and opposite side current data to calculate the differential current according to the phase. According to the current differential protection system The dynamic characteristic equation is used to judge, and when it is judged to be an internal fault, the trip will be activated, and when it is judged to be an external fault, the protection will not operate. At the same time, the power direction relay or power direction element is used to judge the direction of the short-circuit power to select and start the corresponding protection device action;

c. Configure longitudinal protection, intelligent failure protection, over-current protection and quick-break protection for different switches in the switching station, and complete fault handling between cascaded switching stations through mutual negotiation without relying on the master station to achieve fault isolation and power supply recovery. At the same time, the collected voltage, current, power, switch position, fault information, etc. are transmitted to the main power distribution station through optical fiber for real-time monitoring, analysis and remote control of the distribution network.

When a fault occurs, determine whether it acts quickly according to the fault information of itself and the adjacent switch; the failure protection means that when the lower switch refuses to move, the failure protection of the upper switch jumps off the upper switch without delay, removes the fault, and eliminates the traditional overcurrent backup protection The cumulative effect of step-by-step delay shortens the fault removal time.

When the system fails, the terminal that detects the fault current will immediately send its own fault information, and at the same time judge the fault section according to the information received from the adjacent terminal. If the terminal itself detects a fault and the lower-level terminal also detects a fault, the terminal blocks its own longitudinal protection, and the backup failure protection monitors the action of the lower-level switch. The lower-level switch operates normally and the fault is isolated. If the switch refuses to move, the intelligent failure protection will act immediately to remove the failure.

The terminals in the switching station exchange information through electrical signals, and the faults in the station no longer extend to the outside of the station; the terminals between stations exchange information through optical signals to realize the processing of faults between stations, and through the millisecond-level longitudinal protection of the entire network, the nearest fault point The switch is tripped, and the intelligent failure protection is configured as the backup protection at the same time. The setting value automatically adapts to the power supply mode of different power supply directions to ensure the correctness of the setting value coordination, reduce the scope of power failure, and speed up fault handling and power supply recovery.

Fault isolation and power supply recovery do not depend on the main station, and form a small-scale power distribution automation system based on the primary power distribution network frame and its power supply relationship, so as to prevent fault processing from being concentrated in the main station, and the power distribution terminal independently negotiates for fault isolation and power supply recover.

Each of the fault processing terminals is provided with a communication server, and all the communication servers are connected to the power distribution master station, and the detection information and processing information are transmitted to the power distribution master station in time.

When the system communication fails, the backup protection will be used. The backup protection only uses the logical relationship between the fault voltage and fault current inside or between the switching stations, and comprehensively uses the internal logic of the switching station to judge the local control, voltage and power. Direction coordination, switching station node time difference technology; automatic calculation, judgment, and processing to realize fault isolation between four-level cascaded switching stations and power supply recovery in non-faulty areas; at the same time, the collected voltage, current, power, switch position , fault information, etc. are transmitted to the distribution master station through GPRS for real-time monitoring and analysis of the distribution network; the fault handling and power supply recovery of the switching station do not depend on GPRS communication, and GPRS communication is only used as a data transmission channel.

Combining the first half-wave and zero-sequence current group ratio-amplitude-phase method, the zero-sequence current of all outgoing lines on the bus is first collected for amplitude comparison, and several lines that exceed the set value are selected for 1/4 cycle phase comparison. If the phase of the zero-sequence current of the line is different from that of other lines, it is a faulty line. If all the zero-sequence currents are in the same phase, it is a bus fault. A current transformer with small current detection is used, and the primary current enters a linear line at tens of milliamps. Transformation, high current saturation per hour, weak excitation current, secondary can output milliampere level, to ensure the accuracy of current collection.

An intelligent management system for cascaded switching stations of a distribution network, including at least two switching stations, an optical fiber ring network is formed between all the switching stations, and each of the switching stations is equipped with a fault processing terminal , each of the fault processing terminals is connected to the optical fiber ring network through an Ethernet switch, each of the fault processing terminals is provided with a communication server, and all of the communication servers are connected to the power distribution master station.

The fault handling terminal is installed in the cabinet of the switching station or power distribution room; the communication server includes OLT equipment, ONU equipment and optical splitter; the OLT equipment adopts multi-PON port equipment, and the ONU equipment adopts dual The uplink interface of the PON port, the downlink automation terminal adopts the network port.

The beneficial effects of the present invention are:

1. The present invention delegates the function of fault handling to the terminal. When the line fails, it does not rely on communication or the master station, and mainly performs fault processing through independent negotiation between terminals, so that the switch closest to the fault point takes the first protective action. Minimize the scope of power outages.

2. The present invention introduces the idea of line optical fiber differential protection and directional protection into the fault handling of the distribution network, and forms an intelligent management system for cascaded switching stations of the distribution network according to the power supply relationship. The terminal uses the fast communication between the unit networks, only transmits the fault signal, and negotiates independently, which solves the selectivity of the protection action when the feeder is faulty, and realizes fault isolation at one time.

3. The present invention is a supplement and improvement to the existing power distribution automation system, and it is also an improvement to the function of the existing power distribution automation system, so as to better realize the application of advanced functions of the power distribution automation master station, which is convenient for the entire distribution network Manage power distribution.

4. The system of the present invention has no master structure. The industrial optical fiber Ethernet module built in the system forms a ring network, and configures longitudinal protection, intelligent failure protection, over-current protection, and quick-break protection for different switches in the switching station. Negotiation does not rely on the master station to complete fault handling between cascaded switches to achieve fault isolation and power supply recovery.

5. The fault isolation and power supply recovery of the present invention are fast, and the terminal equipment between the switching stations utilizes optical fiber communication for independent negotiation and processing, and isolates faults at a speed of milliseconds, adapting to any complex power grid structure. The entire fault isolation process does not require the participation of the master station.

6. The invention is reasonable in design, simple and practical, quick to deal with faults and reduces power outage time, has a wide application range, is easy to popularize and implement, and has good economic benefits.

Description of drawings:

Figure 1 is a structural diagram of an intelligent management system for distribution network cascaded switching stations;

Figure 2 is one of the implementation structure diagrams of the distribution network cascaded switching station intelligent management system;

Figure 3 is the second implementation structure diagram of the distribution network cascaded switching station intelligent management system.

detailed description:

Embodiment: See Fig. 1-Fig. 3, in the figure, 1-fault handling terminal, 2-communication server, 3-Ethernet switch, 4-optical fiber ring network, 5-power distribution master station.

An intelligent management method for cascaded switching stations of a distribution network, comprising the following steps:

a. An optical fiber ring network 4 is formed between all switching stations, and each switching station is equipped with a fault handling terminal 1, and each fault processing terminal 1 is connected to the optical fiber ring network 4 through an Ethernet switch 3, and the fault The processing terminals 1 use the fast communication between the unit networks, only transmit the fault signal, negotiate independently, solve the selectivity of the protection action when the feeder is faulty, and realize fault isolation at one time;

b. With the help of line fiber optic channel, the sampling data is transmitted to the opposite side in real time, and the sampling data of the opposite side is accepted at the same time. The protection of each side uses the local and opposite side current data to calculate the differential current according to the phase. According to the current differential protection system The dynamic characteristic equation is used to judge, and when it is judged to be an internal fault, the trip will be activated, and when it is judged to be an external fault, the protection will not operate. At the same time, the power direction relay or power direction element is used to judge the direction of the short-circuit power to select and start the corresponding protection device action;

c. Configure longitudinal protection, intelligent failure protection, over-current protection and quick-break protection for different switches in the switching station, and complete fault handling between cascaded switching stations through mutual negotiation without relying on the master station to achieve fault isolation and power supply recovery. At the same time, the collected voltage, current, power, switch position, fault information, etc. are transmitted to the main power distribution station 5 through optical fiber for real-time monitoring, analysis and remote control of the distribution network.

When a fault occurs, determine whether it acts quickly according to the fault information of itself and the adjacent switch; the failure protection means that when the lower switch refuses to move, the failure protection of the upper switch jumps off the upper switch without delay, removes the fault, and eliminates the traditional overcurrent backup protection The cumulative effect of step-by-step delay shortens the fault removal time.

When the system fails, the terminal that detects the fault current will immediately send its own fault information, and at the same time judge the fault section according to the information received from the adjacent terminal. If the terminal itself detects a fault and the lower-level terminal also detects a fault, the terminal blocks its own longitudinal protection, and the backup failure protection monitors the action of the lower-level switch. The lower-level switch operates normally and the fault is isolated. If the switch refuses to move, the intelligent failure protection will act immediately to remove the failure.

The terminals in the switching station exchange information through electrical signals, and the faults in the station no longer extend to the outside of the station; the terminals between stations exchange information through optical signals to realize the processing of faults between stations, and through the millisecond-level longitudinal protection of the entire network, the nearest fault point The switch is tripped, and the intelligent failure protection is configured as the backup protection at the same time. The setting value automatically adapts to the power supply mode of different power supply directions to ensure the correctness of the setting value coordination, reduce the scope of power failure, and speed up fault handling and power supply recovery.

Fault isolation and power supply recovery do not depend on the main station, and form a small-scale power distribution automation system based on the primary power distribution network frame and its power supply relationship, so as to prevent fault processing from being concentrated in the main station, and the power distribution terminal independently negotiates for fault isolation and power supply recover.

Each of the fault handling terminals is provided with a communication server 2, and all the communication servers 2 are connected to the power distribution master station 5, and the detection information and processing information are transmitted to the power distribution master station 5 in time.

When the system communication fails, the backup protection will be used. The backup protection only uses the logical relationship between the fault voltage and fault current inside or between the switching stations, and comprehensively uses the internal logic of the switching station to judge the local control, voltage and power. Direction coordination, switching station node time difference technology; automatic calculation, judgment, and processing to realize fault isolation between four-level cascaded switching stations and power supply recovery in non-faulty areas; at the same time, the collected voltage, current, power, switch position , fault information, etc. are transmitted to the distribution master station through GPRS for real-time monitoring and analysis of the distribution network; the fault handling and power supply recovery of the switching station do not depend on GPRS communication, and GPRS communication is only used as a data transmission channel.

Combining the first half-wave and zero-sequence current group ratio-amplitude-phase method, the zero-sequence current of all outgoing lines on the bus is first collected for amplitude comparison, and several lines that exceed the set value are selected for 1/4 cycle phase comparison. If the phase of the zero-sequence current of the line is different from that of other lines, it is a faulty line. If all the zero-sequence currents are in the same phase, it is a bus fault. A current transformer with small current detection is used, and the primary current enters a linear line at tens of milliamps. Transformation, high current saturation per hour, weak excitation current, secondary can output milliampere level, to ensure the accuracy of current collection.

Fault handling terminal 1 is installed in the switchgear or the cabinet in the power distribution room; communication server 2 includes OLT equipment, ONU equipment and optical splitter; OLT equipment adopts multi-PON port equipment, ONU equipment adopts dual PON port uplink interface, downlink automation terminal Use the network port.

1.1 Local distribution automation scheme

It is applicable to the power distribution network of any cascading relationship, and can include switching stations, and the fault handling is fast and reliable. The following four-level switching stations will be described.

The 8 boards and 31 boards of substation A, the 23 boards and 3 boards of substation B and the 1#, 2#, 3#, 4# switching stations constitute a four-level cascaded switching station hand-in-hand ring network. The system structure diagram is shown in Figure 2 below:

1.1.1 Tie line failure

Assuming that the connection line between 2# and 3# switching stations fails, the fault handling process is as follows:

1) 1#8DL, 1#7DL, 2#8DL, and 2#7DL all feel overcurrent, and 3#8DL has no overcurrent. The switch judges that the faulty section is in 2#7DL and 3# through the exchange and negotiation of fault information. Between 8DL;

2) 1#8DL, 1#7DL, 2#8DL blocking longitudinal protection;

3) 2#7DL longitudinal protection tripped, and the fault was removed;

4) 3#8DL incoming line loss-of-voltage protection trips, and the fault is isolated; 3#11DL unilaterally loses voltage and delays closing, and the power supply of the non-faulty section is restored;

5) The system sends a short message to notify relevant personnel:

a) The 7DL protection of the contact line of the 2# switching station has tripped, and the fault has been isolated;

b) 8DL of the incoming line of 3# switching station trips, 11DL closes, and the power supply is restored in the non-faulty area.

1.1.2 Bus failure

Assuming that the 2# switching station bus fails, the fault handling process is as follows:

1) 1#8DL, 1#7DL, and 2#8DL feel overcurrent, and all outgoing lines on the 2#I-section bus have no overcurrent. Through the exchange and negotiation of fault information, it is judged that the fault occurred on the 2# I-section bus superior;

2) 2#8DL longitudinal protection trips, 3#8DL incoming line loss of voltage protection trips, and the fault is isolated;

3) 3#11DL unilaterally loses voltage and delays closing, and the power supply of the non-faulty section is restored;

4) The system sends a text message to notify relevant personnel:

a) Section Ⅰ busbar of 2# switching station is faulty, 8DL overcurrent protection trips, and the fault has been isolated;

b) The incoming line 8DL of the 3# switching station tripped, and the fault has been isolated;

c) 3# switching station bus coupler 11DL is closed, and the power supply is restored in the non-faulty area.

1.1.3 Subscriber line failure

Assuming that the subscriber line of the 2# switching station fails, the troubleshooting process is as follows:

1) 1#8DL, 1#7DL, 2#8DL, and 2#6DL feel the overcurrent signal, and 1#8DL, 1#7DL, and 2#8DL are judged to be out-of-area faults through the exchange and negotiation of fault information;

2) 1#8DL, 1#7DL, 2#8DL blocking longitudinal protection;

3) 2#6DL quick-break protection action tripped, and the fault was isolated;

4) The system sends a short message to inform the relevant personnel: 6DL protection trip of the contact line of 2# switching station, the fault has been isolated.

1.1.4 Communication failure

Assume that the connection line between 2# and 3# switching stations fails. During normal communication, each device is monitoring the communication status with the upper and lower stations in real time. If the 3# switch fails, there will be a communication problem. The fault handling process is as follows:

1) In the case of a communication failure between 2# and 3# substations, 2#7DL and 3#8DL block the longitudinal protection, and the backup overcurrent protection of 2#7DL starts to remove the fault;

2) 3#8DL trips after voltage loss, isolates the fault, 3#11DL delays closing after unilateral voltage loss, and the power supply of the non-fault section is restored;

3) The system sends a text message to notify relevant personnel:

a) The 7DL protection of the contact line of the 2# switching station has tripped, and the fault has been isolated;

b) 8DL of the incoming line of 3# switching station trips, 11DL closes, and the power supply is restored in the non-faulty area.

1.2 Local power distribution automation scheme without communication

It is applicable to the power distribution network whose cascading relationship does not exceed four levels, and is described below as a four-level switching station.

The 8 boards and 31 boards of substation A, the 23 boards and 3 boards of substation B and the 1#, 2#, 3# switching stations constitute a 3-level cascaded switching station hand-in-hand ring network. The system structure diagram is shown in Figure 3 below:

1.2.1 Tie line failure

Assuming that the connection line between 1# and 2# switching stations fails, the fault handling process is as follows:

1) 1# switching station 7DL has quick-break protection tripping with differential delay;

2) 2# switching station incoming switch 8DL loses voltage and trips, and the fault is isolated;

3) The bus tie switch 11DL of the 2# opening and closing station is switched on under voltage loss on one side, and the power supply of the non-faulty section is restored;

4) The system sends a text message to notify relevant personnel:

a) The 7DL overcurrent protection of 1# switching station contact line tripped, and the fault has been isolated

b) The 8DL of the 2# switching station incoming line loses voltage and trips, the 11DL switches on, and the power supply is restored in the non-faulty area.

1.2.2 Bus failure

Assuming that the busbar of section I of 1# switching station fails, the fault handling process is as follows

1) 1# switching station 8DL has quick-break protection tripping with differential delay;

2) 2# switching station incoming switch 8DL loses voltage and trips, and the fault is isolated;

3) The bus tie switch 11DL of the 2# opening and closing station is switched on under voltage loss on one side, and the power supply of the non-faulty section is restored;

4) The system sends a text message to notify relevant personnel:

a) Section Ⅰ busbar of 1# switching station is faulty, 8DL overcurrent protection trips, and the fault has been isolated;

b) The 8DL of the 2# switchgear incoming line loses voltage and trips, and the fault has been isolated;

c) 2#11DL is closed, and the power supply is restored in the non-faulty area.

1.2.3 Subscriber line failure

Assuming that 1# switching station 6DL fails, the fault handling process is as follows:

1) 1# switching station 6DL delays 0 seconds for overcurrent protection tripping and fault isolation;

2) The system sends a short message to inform the relevant personnel: 1# switching station 6DL is faulty, and the fault has been isolated.

1.3 Description of communication scheme

The optical fiber ring used for fast fault handling and the optical fiber ring of the upper master station can be unified into the same optical fiber cable. In order to ensure sufficient reservation, it is recommended to spare 4-core optical fiber cables.

(1) Optical fiber communication scheme for the intelligent management system of distribution network cascaded switching stations

The optical fiber ring network used in the fast communication of the system requires at least 2-core optical cables, and the spare optical fibers of the current distribution network automation system can be used to provide 2-core optical fibers between the cascaded switching stations to complete the optical fiber ring network.

The backbone lines of the cascaded switching stations or ring network cabinets form a fiber optic ring network, and the information on the ring network is mainly heartbeat messages and fault messages between switches.

The optical communication equipment required for the distribution network cascaded switching station intelligent management system configuration.

(2) Communication scheme of master station on optical fiber

The real-time data, events, fault processing results and other information of the local distribution automation terminal equipment are connected to the existing distribution network automation master station through the communication server.

a. The communication network adopts a layered structure: build an IP-based data network that connects horizontally and connects vertically. From top to bottom are: backbone layer, access layer.

Backbone layer: From the main platform (power supply company) for integrated communication access of distribution and utilization to the sub-platforms for communication access of distribution and utilization (set up in substations with 10kV outgoing lines in urban areas). Realized by optical fiber.

Access layer: from each power distribution communication access sub-platform to each medium-voltage power distribution terminal. From each power distribution communication access sub-platform to each medium-voltage power distribution terminal.

b. The communication method is mainly based on optical fiber communication, and the EPON networking method is adopted.

c. Considering the use of optical fibers for all lines, the preliminary design uses non-metallic flame-retardant optical cables.

d. Communication equipment: OLT equipment adopts multi-PON port equipment, which can continue to use the existing equipment of the substation; ONU equipment, selects dual PON port uplink interfaces, and downlink automation terminals use network ports; optical splitters connect OLT and ONU equipment.

The invention introduces the ideas of line optical fiber differential protection and directional protection into the fault handling of the distribution network, and forms an intelligent management system of cascaded switch stations of the distribution network according to the power supply relationship. The terminal uses the fast communication between the unit networks, only transmits the fault signal, and negotiates independently, which solves the selectivity of the protection action when the feeder is faulty, and realizes fault isolation at one time.

The present invention has a cascaded switching station to construct a unit network, and configures longitudinal protection and intelligent failure protection through fast interactive optical signals on the terminal, realizing the entire network longitudinal protection and intelligent failure protection without time difference accumulation; communication failure Automatic fault processing can still be realized through backup protection; the master station is mainly responsible for advanced functions such as data collection and event browsing, power distribution management, and network reconstruction. The master station and the terminal have a clear division of labor and perform their duties; The temperature, humidity, exhaust, and drainage are connected to the system to realize the monitoring and control of the working conditions of the switching station.

Claims (10)

1. a power distribution network cascade switching station intelligent management, comprises the following steps:

A, between all switching stations, be configured with optical fiber ring network, switching station described in each is provided with troubleshooting terminal, described in each, troubleshooting terminal is all connected with described optical fiber ring network by Ethernet switch, high-speed traffic between range site network between described troubleshooting terminal, only transmit fault-signal, autonomous negotiating, solves the selectivity of protection act during feeder fault, realizes Fault Isolation once;

B, by means of circuit optical fiber passage, sampled data is transmitted in real time to offside, accept the sampled data of offside simultaneously, each side Sustainable use local with offside current data by carrying out differential current calculating mutually, braking characteristic equation according to current differential protection differentiates, action tripping operation when being judged to troubles inside the sample space, when being judged to external area error, protection is failure to actuate, and utilize directional power relay or power directional element to judge the direction of short-circuit power is to select the corresponding protective device action of startup simultaneously;

C, to switchgear distribution pilot protection different in switching station, intelligent failure protection, overcurrent protection and fast tripping protection; Fault Isolation and service restoration is realized by mutually consulting not rely on the main website troubleshooting completed between cascade switching station; simultaneously; the voltage collected, electric current, power, the position of the switch, fault message etc. by Optical Fiber Transmission to distribution main website, carry out the real time monitoring of power distribution network and analysis, remote control.

2. power distribution network cascade switching station intelligent management according to claim 1, is characterized in that: determine self whether quick acting according to the fault message of self and adjacent switch when breaking down; Failure protection is when subordinate's switch failure, and the failure protection of higher level's switch is without time delay tripping higher level switch, and excision fault, eliminates the cumulative effect of time delay step by step of conventional overcurrent backup protection, shortens fault clearing time.

3. power distribution network cascade switching station intelligent management according to claim 1, it is characterized in that: when system jam, detect that the terminal of fault current can send the fault message of self at once, carry out Judging fault section according to the information receiving adjacent end simultaneously, if terminal oneself detects fault, secondary terminal does not detect fault, then pilot protection action at once excision fault; If terminal oneself detects fault, secondary terminal is detection failure also, then the pilot protection of terminal locking self; standby failure protection monitors the action situation of subordinate's switch, subordinate's switch regular event, and fault is isolated; if subordinate's switch failure, then intelligent failure protection action at once excision fault.

4. power distribution network cascade switching station intelligent management according to claim 1, is characterized in that: in opening and closing standing, which, terminal is by signal of telecommunication interactive information, stands internal fault no longer to station extension; Between standing, terminal is by light signal interactive information; realize the process of fault between station; by the whole network Millisecond pilot protection; the switch trip nearest from fault point; configure intelligent failure protection is backup protection simultaneously, and definite value adapts to the supply power mode in different electrical power direction automatically, guarantees the correctness that definite value coordinates; reduce power failure range, accelerate troubleshooting and service restoration.

5. power distribution network cascade switching station intelligent management according to claim 1, it is characterized in that: Fault Isolation and service restoration do not rely on main website, according to distribution rack once and power supply relation thereof, form electrical power distribution automatization system among a small circle, avoid troubleshooting to concentrate on main website, carry out Fault Isolation and service restoration by distribution terminal autonomous negotiating.

6. power distribution network cascade switching station intelligent management according to claim 1, it is characterized in that: described in each, troubleshooting terminal is provided with communication server, all described communication servers are all connected with distribution main website, and Detection Information and process information are transferred in distribution main website in time.

7. power distribution network cascade switching station intelligent management according to claim 1, it is characterized in that: during system communication fault, can backup protection be dropped into, backup protection only adopts the logical relation between false voltage between the inner or switching station of switching station, fault current, and integrated use switching station internal logic judges to control on the spot, voltage and power direction coordinates, the differential technology of switching station node time; Automatic calculating, judgement, process realize the service restoration in Fault Isolation between level Four cascade switching station and non-faulting region; Simultaneously the voltage collected, electric current, power, the position of the switch, fault message etc. by GPRS transmission to distribution main website, to carry out real time monitoring and the analysis of power distribution network; The troubleshooting of switching station and service restoration do not rely on GPRS communication, and GPRS communication is only as data transmission channel.

8. power distribution network cascade switching station intelligent management according to claim 1, it is characterized in that: in conjunction with first half-wave and zero-sequence current colony amplitude comparison phase comparing method, the zero-sequence current gathering all outlets on bus first carries out amplitude com parison, select and cross the several circuit of setting value and carry out 1/4 cycle phase compare again, if the phase place of certain circuit zero-sequence current is different from other circuit, then it is faulty line, if all zero-sequence current same-phases, it is then busbar fault, adopt the current transformer that there is Weak current and detect, primary current just enters linear transformation at tens milliamperes, big current speed per hour is saturated, exciting current is faint, secondary can export milliampere level, ensure to gather the accurate of electric current.

9. a power distribution network cascade switching station intelligent management system, comprise at least two switching stations, it is characterized in that: between all described switching stations, be configured with optical fiber ring network, switching station described in each is provided with troubleshooting terminal, described in each, troubleshooting terminal is all connected with described optical fiber ring network by Ethernet switch, described in each, troubleshooting terminal is provided with communication server, and all described communication servers are all connected with distribution main website.

10. power distribution network cascade switching station intelligent management system according to claim 9, is characterized in that: described troubleshooting terminal is arranged in the rack in described switching station or switchgear house; Described communication server comprises OLT device, ONU equipment and optical splitter; Described OLT device adopts many PON jaws equipment, and described ONU equipment selects connecting port on double-PON port, and second line of a couplet automatization terminal adopts network interface.