Medium voltage distribution network direction longitudinal connection quick action protection method, device and system

Abstract

The invention belongs to the technical field of medium-voltage power distribution networks, and is characterized in that on the basis of a directional current protection function of a microcomputer protection device commonly used in an existing medium-voltage power distribution network, the existing conventional current protection is upgraded into distribution network direction longitudinal connection quick-action protection through protection information action logic locking between different nodes; the short-circuit fault point can be rapidly and accurately removed within the coverage range of the medium-voltage distribution network direction longitudinal connection protection device, the influence range of fault power failure is limited to the minimum, and the reliability, sensitivity, selectivity and quickness of medium-voltage distribution network protection action are ensured. The problems that according to an existing conventional medium-voltage relay protection technology, setting calculation is difficult, and reliability, sensitivity, selectivity and quickness of protection are difficult to meet at the same time are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of medium-voltage distribution networks, and in particular relates to a method, a device and a system for directional longitudinal quick-acting protection of a medium-voltage distribution network. Background Art

[0002] The medium-voltage distribution network receives electric energy from the high-voltage power grid, converts it into a lower voltage level suitable for industrial, commercial and residential use through a step-down transformer, and distributes it to end users. Since the medium-voltage distribution network is at the tail end of the power grid, it is greatly affected by the operation mode of the transmission network and the high-voltage distribution network. The short-circuit current is different under different operation modes, and the difference between the short-circuit current under the maximum and minimum modes is quite different. This causes the conventional microcomputer medium-voltage line protection device, which mainly uses current protection, to have a very large change in protection range under different operation modes of the power grid. Even if the line protection setting is correctly calculated, it is difficult to accurately determine the fault range and quickly remove the faulty equipment. Expanding the power outage range is almost the norm for distribution network fault isolation.

[0003] At present, conventional medium-voltage distribution networks are generally equipped with three-stage microcomputer current and voltage protection in the main switch and section interconnection switch equipment according to the line ("3kV~110kV Power Grid Relay Protection Device Operation and Setting Procedure" (DL / T584-2007)). The protection device generally has a directional element, and the protection range is divided by the coordination of different current settings and action times.

[0004] like Figure 1 As shown in the figure, according to the "3kV~110kV Power Grid Relay Protection Device Operation Setting Regulations" (DL / T584-2007), the three-stage current protection stage I is set according to the maximum short-circuit current at the end of the current line to ensure that the stage I protection does not extend to the protection range of the next line at any time; the stage II protection cooperates with the stage I protection of the next line, and the delay is 0.5s to ensure that the protection range of the stage II protection can cover the entire length of the current line in the minimum mode; the stage III protection cooperates with the stage II or stage III protection of the next line, as the backup protection of the next line, and can cover the entire length of the next line in the minimum mode, and the delay is set according to the action time of avoiding the stage II or stage III of the next line (increase 0.5s); the current element provides the setting value of the protection, and the stage I-III protection needs to be given different setting values ​​according to the setting principle determined by DL / T584-2007. The directional element can be selectively put into use; the delay setting is set according to the stage I, II, and III protection with different delays. Its setting calculation is difficult and it is difficult to meet the reliability, sensitivity, selectivity and speed requirements of relay protection.

[0005] Since the operation mode of medium-voltage distribution network lines is greatly affected by the upper power grid, the maximum mode and minimum mode short-circuit current differ greatly, resulting in a very small protection range of the three-stage microcomputer current protection fast-acting stage (stage I), which is often less than 20% of this section of the line. The probability that the line short-circuit fault point is outside the protection range of stage I is relatively high, and the protection fast-acting performance is poor; especially in urban distribution networks with high load density, the distance between ring network cabinets (branch boxes) is very close, and the difference in short-circuit current is very small; the setting principles specified in the "3kV~110kV Power Grid Relay Protection Device Operation Setting Regulations" (DL / T584-2007) cannot be achieved; therefore, the three-stage microcomputer protection of the distribution network with current as the main criterion is difficult to solve the problems existing in the existing distribution network, especially in complex urban distribution networks, where ring network cabinets (branch boxes) are relatively dense and the distance between them is often not large, which makes it very difficult to distinguish different fault ranges by short-circuit current settings. Expanding the power outage range or even causing a full-line power outage is a common situation in the distribution network. Summary of the invention

[0006] Based on the problems mentioned in the above background technology, the present invention provides a method for longitudinal quick-acting protection in the direction of a medium-voltage distribution network.

[0007] The adopted technical scheme is as follows: a method for medium-voltage distribution network direction longitudinal quick-acting protection, the method comprising: defining the area between the upper and lower ring network cabinets in the distribution line as an interval, wherein each interval is provided with a protection device; using the power direction element and the current element of the protection device as starting elements, and the starting conditions are: the current element is started and the power direction element is started in the positive direction; wherein the upper-level interval protection device is locked by the activation of the lower-level interval protection device, and the locking indicates that the fault point is not in its interval, but in its lower-level interval: if the protection device of a certain level interval does not receive the next-level protection locking signal within the specified time after being activated, it indicates that the fault point is in this interval, and the circuit breaker trips to cut off the short-circuit fault point.

[0008] Furthermore, the setting value of the current element is set to avoid the maximum load current of the line.

[0009] Furthermore, the power direction element has a sensitivity angle of 45°, adopts a 90° wiring method, and is connected with the current element in a phase-based starting mode. The direction points to the ring network cabinet or switch cabinet, and the busbar points to the line.

[0010] Furthermore, the prescribed time is a primary delay + a secondary delay; wherein the primary delay is composed of a start-up time difference + a real-time communication delay + a time margin, and the secondary delay is 15 milliseconds.

[0011] Furthermore, the one-time delay does not exceed 45ms.

[0012] The beneficial effects of the present invention are:

[0013] New action interlocking logic devices are added to all protection devices of distribution lines, and logical interlocking between upper and lower protection is realized through real-time communication devices. The action of the upper protection device is locked by the start of the lower protection device, and the switch of this level can only be tripped when the lower protection device is not started. The scope of fault power outage is minimized, and it has wide adaptability in the distribution network, effectively solving the difficulty of setting calculation in the existing technology, which is difficult to meet the reliability, sensitivity, selectivity and speed requirements of relay protection.

[0014] Based on the problems mentioned in the above background technology, the present invention also provides a medium voltage distribution network direction longitudinal quick-acting protection device.

[0015] The adopted technical scheme is as follows: a device for longitudinal quick-acting protection in the direction of a medium-voltage distribution network, comprising a microcomputer protection unit, the microcomputer protection unit being used to receive signals from a current detection unit and a voltage detection unit to judge faults; a re-actuating unit connected to the microcomputer protection unit and used to enhance or repeat the protection action signal; a direction element connected to the microcomputer protection unit and used to judge the direction of the fault current; a circuit breaker interface connected to the microcomputer protection unit and used to receive a tripping instruction and execute a tripping action of the circuit breaker; a communication interface connected to the microcomputer protection unit to realize real-time communication and used to receive a locking signal of the next level interval. When it receives the locking signal, the re-actuating unit at this level is locked and does not trigger tripping, so that the microcomputer protection unit executes the longitudinal quick-acting protection method in the direction of the medium-voltage distribution network.

[0016] Based on the problems mentioned in the above background technology, the present invention also provides a medium voltage distribution network direction longitudinal quick-acting protection system.

[0017] The adopted technical solution is as follows: a longitudinal quick-acting protection system for medium-voltage distribution network direction, including a protection device and a communication medium for information interaction therewith, wherein the communication medium is used to realize real-time communication or direct circuit connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention can be further illustrated by the non-limiting examples given in the accompanying drawings;

[0019] Figure 1 This is the operating principle diagram of the existing microcomputer three-stage current protection;

[0020] Figure 2 This is the principle diagram of the protection action in the longitudinal direction of the medium voltage distribution network of the present invention.

[0021] Figure 3 It is a schematic diagram of the configuration of the longitudinal quick-acting protection in the medium-voltage distribution network direction in the single radial power supply network of the present invention;

[0022] Figure 4 It is a schematic diagram of the configuration of the longitudinal quick-acting protection in the medium-voltage distribution network direction in the chain-type power supply network of the present invention;

[0023] Figure 5 The electrical diagram of switches 1DL-2DL in the four-switch ring main unit K1 for longitudinal quick-acting protection in the medium-voltage distribution network direction of the present invention;

[0024] Figure 6 It is a schematic diagram of the configuration of the longitudinal quick-acting protection in the medium-voltage distribution network direction in the four-switch ring network cabinet K1 of the present invention; DETAILED DESCRIPTION

[0025] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings.

[0026] Figure 1 Shown is the action logic diagram of the existing protection device.

[0027] The method embodiment provided by the present invention is as follows:

[0028] like Figure 2 As shown, a locking device is added to the original conventional three-stage current microcomputer protection device to form the protection device of the present invention:

[0029] The implementation process of the medium voltage distribution network directional longitudinal quick-acting protection method of this embodiment is as follows:

[0030] The area between the sectionalizing switches or the interconnecting switches of adjacent ring main units in the distribution network is defined as an interval, and the ring main units or sectionalizing switches at both ends of the interval are defined as nodes. The sectionalizing switches and the feeder switches of the ring main units are equipped with protection devices, and the ring main units and sectionalizing switches are equipped with three-phase voltage transformers to provide protection power for the protection devices and provide voltage for the power direction elements of the protection devices.

[0031] The power direction element and current element of the protection device installed in each node switch are used as the starting elements, and the starting conditions are: the current element is started and the power direction element is started in the positive direction;

[0032] When a short-circuit fault occurs in a medium-voltage distribution network, the node switches through which the short-circuit current flows from the fault point to the power supply points providing the short-circuit current are configured with protection devices whose directional element is set in the direction from the power supply providing the short-circuit current to the current short-circuit point, and which are activated when a forward short-circuit current is detected; and whose directional element is set in the direction from the current short-circuit point to the power supply providing the short-circuit current, and which are not activated when a reverse short-circuit current is detected.

[0033] After the protection devices between the power supply point that provides the short-circuit power supply and the nodes between the fault point are activated, they all send out a blocking signal to block the protection devices of the upper-level interval. The upper-level interval protection devices are blocked by the activation of the lower-level interval protection devices, and the output does not trip. Being blocked by the lower-level interval protection indicates that the fault point is not in its interval, but in its lower-level interval. Failure to trip the output will not cause the power outage to expand. If the protection device of a certain interval is not blocked by the lower-level protection within the specified time after being activated, it indicates that there is no short-circuit current provided by the power supply on this side flowing through the lower-level interval, and the fault point is not in the lower-level and subsequent intervals, but in the current-level interval. It trips and cuts off the short-circuit fault point. Theoretically, it can ensure that the switch closest to the short-circuit point is the first to act to cut off the short-circuit fault each time, ensuring that the scope of the fault power outage is limited to the minimum.

[0034] The main feature of its blocking logic is that the blocking is determined by the combined action logic of the protection devices configured for each node switch. The switch at this level directly connected to the upper node switch as the opposite switch of the upper interval can only send a blocking signal in the closed state. If it trips, the blocking signal is blocked, and the upper node switch is not blocked by the switch at this level. When the current element of any protection direction of other switches at this level is activated, a blocking signal is sent to block the upper node switch.

[0035] The setting value of the current element is set to avoid the maximum load current of the line, and does not need to be set based on the detailed calculation of the line short-circuit current. Since the load current is much smaller than the short-circuit current, there is no need to perform complex short-circuit calculations to determine the protection setting value, which solves the problem of difficulty in setting value calculation.

[0036] Since the starting value of the power direction element is very small, the direction is the busbar pointing line of the ring main unit (or substation), the sensitivity angle is 45°, and the 90° wiring method is adopted. It is connected with the current element in a phase-based starting mode, which can accurately determine the direction of the short-circuit current. According to whether there is a short-circuit current flowing through the protection installation point and the direction of the short-circuit current, the switch of the ring main unit (branch box) closest to the short-circuit point can be locked, and then the fault point can be cut off through the switch, limiting the scope of the fault power outage to the minimum.

[0037] The time specified is one delay + two delays. The time for the transmission of the blocking logic is one delay, which is mainly composed of the start-up time difference of the existing protection device (maximum no more than 25 milliseconds) + real-time communication delay (15 milliseconds) + time margin (5 milliseconds), which is generally within 45 milliseconds, but not limited to this delay value, depending on the time difference of the same line protection start-up and the communication time of the blocking signal transmission; the second delay is set to 15 milliseconds, which is used to determine whether the next level of protection has a blocking signal delivered. If not, the exit is activated, and if so, the exit of this level is locked.

[0038] The interlocking logic transmission method includes but is not limited to optical fiber communication, carrier communication, and direct transmission of electrical signals, which is mainly determined based on the actual situation of the distribution network and the distance between the upper and lower ring network cabinets (branch boxes). For example, if the distance between the ring network cabinet and the branch box in the urban distribution network is relatively close, optical fiber communication and secondary cable direct connection can be used to transmit the interlocking signal. The distance between the section interconnection switches in the rural distribution network is relatively far, and optical fiber is generally not laid along the line. The interlocking signal can be transmitted via a medium-voltage carrier. Because the amount of interlocking signal data is extremely small, there will be no situation where excessive data volume congests the communication network and causes large delays.

[0039] Embodiment 1:

[0040] It is applied to single-radiation single-power medium-voltage distribution lines, for example Figure 3 As shown:

[0041] For single-radiation single-power medium-voltage distribution lines, if a line short-circuit fault occurs, the line section switches before the short-circuit point will have short-circuit current flowing through them, and the protection devices will be activated at the same time. There will be no short-circuit current in the line section switches after the short-circuit point, and the protection devices will not be activated. The protection device of the section switch closest to the short-circuit point and through which the short-circuit current flows will not receive the protection start-up and lockout signal of the section switch at the next level, and will quickly operate to cut off the fault point; the other line section switches through which the short-circuit current flows will receive the protection start-up and lockout signal of the switch at the next level, and will lock the tripping outlet of the switch at this level, so that the scope of the power outage will not be expanded by malfunction.

[0042] If the short-circuit point occurs between the ring main unit 1K and 2K, short-circuit current flows through 1k00, 1k10, and 1k12, and the direction of the short-circuit current of 1k10 points to the busbar, the directional element will not start, and its protection device will not start. The protection of 1k00 and 1k12 starts, and the 1k00 protection device receives the locking signal from the locking device of the ring main unit after 45ms and locks the output tripping circuit, and the 1k00 switch does not trip; 1k12 does not receive the action locking signal of its lower-level switch 1k20 after 45ms (no short-circuit current, no start), 1k12 starts to trip, and the short-circuit fault point d12 is cut off.

[0043] Embodiment 2:

[0044] It is applied to dual power chain or ring network distribution network implementation, for example Figure 4 As shown:

[0045] For dual-power chain or ring network medium-voltage distribution lines, if a line short-circuit fault occurs, the two power sources provide short-circuit current to the short-circuit point through different paths. Short-circuit current flows through the line section switches on both sides before the short-circuit point, and the protection devices are activated at the same time. The protection devices of the ring network cabinets (branch boxes) on both sides closest to the short-circuit point cannot receive the protection start-up lockout signal of the next-level section switch (because the short-circuit power protection of the lower-level switch flowing in the opposite direction is not activated) and quickly act to cut off the fault point; the other line section switches on both sides with short-circuit current flowing through them receive the protection start-up lockout signal of their respective lower-level switches and lock the tripping outlet of the switch at this level, so that they will not erroneously operate to expand the scope of power outage.

[0046] A short circuit occurs at point D12, and both 1# substation and 2# substation provide short-circuit current to short-circuit point d12. Forward short-circuit current flows through 1k00, 1k12, 1k30, and 1k20 protections, and the protection devices are activated. 1k10 and 1k22 protection devices sense reverse short-circuit current, and the protection will not be activated. The magnitude and direction of the short-circuit current in 1k11 and 1k21 are related to the position of the short-circuit point d12 and the magnitude of the short-circuit current provided by the two substations, but one must be activated and the other not. 1k00 is blocked by the action of switch 1k12 of the lower-level ring network cabinet 1k to lock the export tripping circuit, and 1k00 will not malfunction to expand the power outage range. Similarly, 1k30 will not malfunction. One of the switches in 1k12 and 1k20 will not send a blocking signal due to the action of the branch switch protection of the opposite ring network cabinet, and the switch will trip first to disconnect the switch on the short-circuit point d12 side. The other switch then operates in a step-by-step manner, cutting off the short-circuit current at the fault point d12.

[0047] The overall method adopts a method of adding an action interlocking logic device to all protection devices of the distribution line, and realizing the logical interlocking between the upper and lower protections through a real-time communication device. The action of the upper-level protection device is locked by the activation of the lower-level protection device, and the switch of this level can only be tripped when the lower-level protection device is not activated. In the event of a short circuit in the line, only the switch of the ring main unit (branch box) closest to the fault point will not receive the action signal of the switch of the ring main unit (branch box) of the lower level and will quickly act to cut off the fault point. Although the switches of other upper-level ring main units (branch boxes) sense the short-circuit current and start, they are all locked by the activation of the protection devices of their respective lower-level ring main units (branch boxes), and the switches of the ring main units (branch boxes) of this level will not be tripped, so as to minimize the scope of power outage caused by the fault, and have wide adaptability in the distribution network, effectively solving the problems existing in the prior art.

[0048] Embodiment three, as Figure 5-6 As shown:

[0049] Among them, CKJ is a direct outlet, connected to the circuit breaker tripping coil, to start the circuit breaker tripping;

[0050] QJ is a fast-acting protection action heavy-acting relay;

[0051] Q is the quick-acting protection action outlet with direction;

[0052] X7 and X2 receive the next level interlocking signal. After receiving the interlocking signal, the heavy-duty relay of this level is interlocked, and the output will not trip even if the protection of this level is activated.

[0053] The locking signal of this level is connected in series with the output signal of the directional fast-acting protection device configured on other switches of the ring main unit at this level through the normally open contact of the switch connected to the busbar of the ring main unit at this level, and then transmitted to the upper level after "OR logic", and connected to X7 and X2 of the upper level to realize the locking of the protection of the upper level.

[0054] k00 only receives the blocking signal from k10, and the 4-way switch protection of the ring main unit k1 blocks k00. If the short circuit occurs outside the exits of k11, k12, and k13, the protection of k11, k12, and k13 blocks k00 through the normally open contact of dl10. If the short circuit occurs between k10 and k00, k11, k12, and k13 are reversed, and the protection does not work; k00 does not receive the blocking signal from K1, and the quick-acting protection is activated to remove the fault; k10 is the last level, has no blocking signal, and works normally.

[0055] If a short circuit occurs outside k12, the protection of k00, k12, k20, k30, k31, and k40 will be activated, and the protection of k10, k11, k22, and k32 will be reversed, and the protection will not be activated.

[0056] K12 cannot receive the blocking signal from K22 on the opposite side, and the K12 switch is disconnected at the quick exit; K20 cannot receive the blocking signal from K10 on the opposite side, and the K20 switch is disconnected at the quick exit; K12 protection action blocks K00, and K00 cannot exit at quick disconnection; K20 protection blocks K30, and K30 cannot exit at quick disconnection; K30 blocks K40, and K40 protection cannot exit;

[0057] The opposite side of k20 is reversed to k10, the protection does not start, there is no short-circuit current flowing through k11 and k13, the protection does not start, so there is no opposite side locking signal, the outlet trips, and the switch k20 is disconnected; (If there is power on the opposite side of k11 and k13, the protection is reversed and does not start)

[0058] The next level of protection for k12 is k21, k22, and k23. If k22 is reversed, there is no short-circuit current in k21 and k23, and the protection will not start. Therefore, there is no opposite side blocking signal on the opposite side of k12, the outlet trips, and the switch k12 is disconnected, and the fault point is cut off. (If there is power on the opposite side of k21 and k23, the protection is reversed and will not start).

[0059] A cross-phase grounding short circuit occurs in d2, one short circuit point is after k12, and the other short circuit point is between k10 and k00. The protections of k12, k00 and k10, k20, k30, and k40 are started at the same time, and trip according to the interlocking sequence relationship, cutting off one fault point. The phase-to-phase short circuit becomes single-phase grounding, and the power grid continues to operate.

[0060] If a short circuit occurs outside k23, the protection of k23, k12, k00, k30, and k40 will be activated, and the protection of k10, k20, k22, and k32 will be reversed and will not be activated.

[0061] The k12 protection action locks k00, k00 quickly breaks and cannot exit; k23 protection locks k12, k12 quickly breaks and cannot exit; k23 locks k30, k30 cannot exit; k30 locks k40, k40 protection cannot exit; k23 has no opposite side locking signal, the exit trips, disconnects switch k23, and cuts off the fault point.

[0062] In addition, the present invention also provides an embodiment of the device:

[0063] The medium-voltage distribution network directional longitudinal quick-acting protection device includes a microcomputer protection unit, which is used to receive signals from a current detection unit and a voltage detection unit to determine a fault; a re-actuating unit, which is connected to the microcomputer protection unit and is used to enhance or repeat the protection action signal; a directional element, which is connected to the microcomputer protection unit and is used to determine the direction of the fault current; a circuit breaker interface, which is connected to the microcomputer protection unit and is used to receive a tripping instruction and execute a tripping action of the circuit breaker; and a communication interface, which is connected to the microcomputer protection unit to realize real-time communication and is used to receive a locking signal from a next-level interval. When it receives the locking signal, the re-actuating unit at this level is locked and does not trigger the tripping.

[0064] In addition, the present invention also provides a system embodiment:

[0065] The medium-voltage distribution network direction longitudinal fast-acting protection system comprises a protection device and a communication medium for information interaction therewith, wherein the communication medium comprises real-time communication for realizing a medium-voltage distribution network direction longitudinal fast-acting protection method.

[0066] The present invention has been described in detail above. The description of the specific embodiments is only used to help understand the method of the present invention and its core concept. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for longitudinal quick-acting protection in the direction of a medium voltage distribution network, characterized in that: The method includes: The area between adjacent key switchgear in the distribution network is defined as an interval, and the key switchgear at both ends of the interval is defined as a node, where each node is equipped with a protection device; The power direction element and the current element of the protection device are used as starting elements, and the starting conditions are: the current element is started and the power direction element is started in the forward direction; Among them, the upper-level interval protection device is locked by the lower-level interval protection device. Its locking indicates that the fault point is not in its interval, but in its lower-level interval: If the protection device of a certain level of interval is activated and does not receive the next level of protection lockout signal within the specified time, it means that the fault point is within this interval, and the circuit breaker will trip to cut off the short-circuit fault point.

2. A medium voltage distribution network direction longitudinal quick-acting protection method according to claim 1, characterized in that: The setting value of the current element is set to avoid the maximum load current of the line.

3. A medium voltage distribution network direction longitudinal quick-acting protection method according to claim 2, characterized in that: The power direction element has a sensitivity angle of 45° and adopts a 90° wiring method. It is connected with the current element in a phase-based starting mode. The direction points to the ring network cabinet or switch cabinet, and the busbar points to the line.

4. A medium voltage distribution network direction longitudinal quick-acting protection method according to claim 1, characterized in that: The power direction element takes the current flowing from the power supply to the fault point as the positive direction, and takes the current flowing from the fault point back to the power supply as the reverse direction.

5. A method according to claim 1, characterized in that: The specified time is a primary delay + a secondary delay; the primary delay is composed of a start-up time difference + a real-time communication delay + a time margin, and the secondary delay is 15 milliseconds.

6. A method according to claim 5, characterized in that: The one-time delay does not exceed 45ms.

7. A medium voltage distribution network direction longitudinal quick-acting protection device, characterized in that: include A microcomputer protection unit, the microcomputer protection unit is used to receive signals from the current detection unit and the voltage detection unit to determine faults; The re-operation unit is connected to the microcomputer protection unit and is used to enhance or repeat the protection action signal; Direction element, connected to the microcomputer protection unit, used to determine the direction of the fault current; A circuit breaker interface is connected to the microcomputer protection unit and is used to receive a tripping instruction and execute a circuit breaker tripping action; A communication interface is connected to the microcomputer protection unit to realize real-time communication, and is used to receive the locking signal of the next level interval. When it receives the locking signal, the heavy-duty unit at this level is locked and does not trigger tripping, so that the microcomputer protection unit executes the medium-voltage distribution network direction longitudinal quick-acting protection method described in any one of claims 1-6.

8. A medium voltage distribution network direction longitudinal fast-acting protection system, which uses the medium voltage distribution network direction longitudinal fast-acting protection device according to claim 7, characterized in that: It comprises a protection device and a communication medium for information interaction therewith, wherein the communication medium comprises real-time communication for implementing the medium-voltage distribution network direction longitudinal quick-acting protection method as described in any one of claims 1-5.

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