Method and system for accelerated protection after grading of power distribution network based on magnetically controlled switch

Abstract

The invention discloses a magnetically controlled switch-based power distribution network post-grading acceleration protection method and system, and the method comprises the steps: carrying out the overcurrent protection of a magnetically controlled outgoing line switch, and carrying out the voltage detection reclosure, which serve as the first-stage outgoing line protection; the magnetic control first section switch and the magnetic control second section switch are provided with delay protection and latch-up protection which are used as second-stage branch head end protection; the magnetic control interconnection switch is configured to detect short-time power-on time opening and reverse locking and start transfer timing, and serves as third-level demarcation protection; if the distribution network overhead line has a short-circuit fault, stage differences are set among three-stage protection, and the three-stage protection magnetically controlled switches act in a matched manner, so that fault isolation is accelerated to be completed. Through three-level protection of outgoing line protection, branch head end protection and demarcation protection, a 0.2 s level difference is set, reliable cooperation of switches of the whole line can be realized by using the difference of protection time delay, branch line and user faults can be removed nearby, and the problem of simultaneous tripping or override tripping is avoided.

Description

Technical Field

[0001] The present invention belongs to the field of distribution network protection, and in particular, relates to a distribution network hierarchical protection method and system based on the rapid opening and closing capability and post-acceleration function of a magnetically controlled switch. Background Art

[0002] With the vigorous development of the distribution network, the mileage of distribution lines has increased year by year, and the number of newly added outgoing and sectionalized switches has increased sharply, bringing new challenges to the protection of the distribution network. Due to the common configuration differences of the surging number of distribution network line switches, and the lack of unified standard specifications for reference, when faults occur on the distribution network lines during actual operation, a large number of outgoing line switches trip at the same time as the downstream sectionalized switches, the sectionalized switches trip at the same time, and even the downstream switches do not trip and jump to the upper level switches. The protection function of the sectionalized switches is limited, and they fail to effectively play the role of isolating faults and reducing the scope of power outages, and the safe and stable operation of the distribution network is challenged.

[0003] With the development of distribution network protection technology, hierarchical protection technology has emerged to address the above problems, and hierarchical protection technologies such as three-level protection and five-level protection technology have been gradually widely used. The setting configuration of each switch is more precise and reasonable, and the connection and coordination between switches are closer. However, in the current hierarchical protection technology, the outgoing line protection and the section switch protection cannot be effectively coordinated, which is prone to simultaneous tripping or over-tripping.

[0004] The prior art document (CN112952780A) discloses a method for calculating the setting of layered and graded protection of distribution networks. The method in this document only proposes a graded protection based on a three-stage overcurrent protection delay of the outgoing line switch, the section switch and the branch switch. The method focuses on using the overcurrent graded protection of the outgoing line switch, the section switch and the branch switch for fault handling. There is less content on the coordination of post-acceleration protection after the overcurrent protection is triggered, and it is only used as a remedial measure when the same-layer protection trips simultaneously. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the present invention is based on the principle of unified distribution network line switch protection configuration, so that the outgoing line protection and the section switch protection can be effectively coordinated to achieve orderly tripping of the line switch. Since the tripping time of a general pole-mounted circuit breaker switch or a ring network cabinet switch is about 150ms, the protection classification difference time should be at least not less than 0.2s to achieve effective coordination of the upper and lower switches in time.

[0006] The first aspect of the present invention discloses a distribution network classification post-acceleration protection method based on a magnetically controlled switch, comprising:

[0007] The magnetically controlled outgoing line switch is equipped with overcurrent protection and voltage detection reclosing switch as the first-level outgoing line protection;

[0008] The first magnetically controlled section switch and the second magnetically controlled section switch are configured with a closing power supply fault detection acceleration opening delay and a short-time power supply detection time opening and reverse locking, as the second-level branch head end protection;

[0009] The magnetically controlled contact switch is configured to detect the short-time power supply time, trip the switch, reversely lock, and start the power transfer timing, as the third-level boundary protection;

[0010] If a short circuit occurs in the overhead line of the distribution network, a level difference is set between the three levels of protection, and the three-level protection magnetically controlled switches cooperate to accelerate the isolation of the fault.

[0011] Preferably, the post-acceleration protection parameter configuration of the graded protection magnetic control switch is specifically as follows:

[0012] The magnetically controlled outgoing line switch is equipped with overcurrent protection and voltage detection reclosing switch. The overcurrent protection is divided into three stages: overcurrent stage I is 0s, overcurrent stage II is 0.4s, and overcurrent stage III is 0.6s. The voltage detection reclosing switch is set to 1 time with a delay of 2s.

[0013] The post-acceleration parameters of the first magnetically controlled section switch are configured, including: 0.3s closing power detection fault acceleration trip delay as post-acceleration protection; short-time power detection time less than 0.12s or greater than 0.4s trip and reverse lock, and set a 0.1s step difference in combination with post-acceleration protection; 5s fault handling time window;

[0014] The post-acceleration protection parameters are configured for the magnetically controlled second section switch, including: 0.2s closing power detection fault acceleration tripping delay as post-acceleration protection; 0.3s~0.4s short-time power detection time for tripping and reverse locking, and a 0.1s step difference is set in combination with the post-acceleration protection; 5s fault handling time window.

[0015] Preferably, the parameters of the magnetically controlled contact switch are configured, including: setting the short-time power supply time to open the switch and reverse lock, if 0.2s < the duration of the short-time power supply < 0.3s, reverse lock and do not start the timing; if the short-time power supply time is not between 0.2s and 0.3s, delay closing and restore power supply to the faulty back end.

[0016] Preferably, the hierarchical protection magnetic control switch action when a short circuit fault occurs at the incoming line end of the distribution network overhead line is specifically as follows:

[0017] After a fault occurs, the magnetically controlled outgoing line switch is protected to open, and the magnetically controlled first section switch and the magnetically controlled second section switch remain in the closed state;

[0018] The magnetically controlled outgoing line switch will reclose after a delay of 2s. If it is a momentary fault, it will return to normal.

[0019] Preferably, if it is a permanent fault, the magnetically controlled outlet switch is opened again for protection and no longer overlaps; the magnetically controlled first section switch detects that the short-term power duration is less than 0.12s or the short-term power duration of the overcurrent section II or overcurrent section III of the magnetically controlled outlet switch is greater than 0.4s, and automatically opens and reversely locks, wherein 0.12s is the minimum first section setting time, and 0.4s is the maximum first section setting time; and if the short-term power duration is not within the setting time of 0.3 to 0.4s of the magnetically controlled second section switch, the magnetically controlled second section switch remains closed;

[0020] After one side of the magnetically controlled contact switch loses voltage, a short-term power supply is detected and the duration is not within the set time of 0.2s to 0.3s, and the switch is closed with a delay to restore power supply to the faulty rear end.

[0021] Preferably, when a short circuit fault occurs at the transmission end of the overhead line of the distribution network, the actions of the hierarchical protection magnetic control switch are specifically as follows:

[0022] The magnetically controlled outlet switch is opened for overcurrent section II or overcurrent section III protection, and the magnetically controlled first section switch and the magnetically controlled second section switch remain in the closed state;

[0023] The magnetically controlled outgoing line switch will reclose after a delay of 2s. If it is a transient fault, it will return to normal;

[0024] If it is a permanent fault, the magnetically controlled first section switch will accelerate the protection opening delay of 0.3s and lock forward. The magnetically controlled outgoing line switch will not operate until the protection delay of 0.4s or 0.6s is reached. The magnetically controlled second section switch will automatically open and lock reversely if it detects that the short-term incoming call time is between 0.3s and 0.4s of the second section setting time.

[0025] After one side of the magnetically controlled contact switch loses voltage, a short-term power supply is detected and the duration is not within the set time of 0.2s to 0.3s, and the switch is closed with a delay to restore power supply to the faulty rear end.

[0026] Preferably, the hierarchical protection magnetic control switch action when a short circuit fault occurs at the end of the distribution network overhead line is specifically:

[0027] The protection of section II or section III of the magnetically controlled outgoing line switch is opened, and the magnetically controlled first section switch and the magnetically controlled second section switch remain in the closed state;

[0028] The magnetically controlled outgoing line switch will reclose after a delay of 2s. If it is a transient fault, it will return to normal;

[0029] If it is a permanent fault, the acceleration protection tripping delay of the second section switch of the magnetic control is 0.2s and positively locked. The magnetic control outgoing line switch does not operate before the set protection delay of 0.4s or 0.6s. The magnetic control first section switch does not operate before the first section protection delay of 0.3s.

[0030] After one side of the magnetically controlled contact switch loses pressure, a short-term power supply is detected, but the duration is within the set time of 0.2s to 0.3s. The lockout delay will no longer close the switch and transfer power, thus completing the fault isolation.

[0031] Preferably, the magnetically controlled outgoing line switch, the magnetically controlled first section switch, the magnetically controlled second section switch and the magnetically controlled connecting switch are all equipped with a magnetically controlled circuit breaker.

[0032] The second aspect of the present invention discloses a distribution network hierarchical protection system based on post-acceleration hierarchical protection of magnetically controlled switches, comprising:

[0033] Outgoing line protection module, used to configure overcurrent protection and voltage detection reclosing for magnetically controlled outgoing line switches;

[0034] Branch protection module, used to configure delay protection and locking protection for magnetically controlled section switches;

[0035] Boundary protection module, used to configure locking protection and transfer timing for magnetically controlled contact switches;

[0036] The protection module is used to complete fault isolation by actuating the graded protection magnetic control switch when a fault occurs at the incoming end of the distribution network overhead line.

[0037] The beneficial effect of the present invention lies in that, compared with the prior art, the present invention adopts three-level protection of "outgoing line protection + branch head end protection + boundary protection", sets a level difference of 0.2s, and utilizes the difference in protection delay to achieve reliable coordination of switches on the entire line, thereby achieving local cutting of branch line and user faults, avoiding the problem of simultaneous tripping or over-tripping.

[0038] By utilizing the characteristic that the overall opening time of the primary and secondary fused magnetically controlled circuit breaker is less than 60ms, the opening time is shortened by half compared to the general pole-mounted circuit breaker switch or ring main unit switch of about 150ms in the distribution network. That is, the hierarchical protection level difference can also be shortened by half, greatly reducing the overall fault handling time.

[0039] The post-acceleration protection function is implemented with hierarchical protection, which makes the setting configuration of each switch more precise and reasonable, the connection and coordination between switches more closely, and the fault handling process more accurate. This greatly improves the efficiency and level of fault handling.

[0040] The implementation of the overall hierarchical protection scheme does not require complicated operations. It can be verified and implemented by simply configuring set values ​​on existing magnetically controlled circuit breaker equipment. It is simple to implement and highly economical. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of the three-level protection technology;

[0042] Figure 2It is the topology diagram of the distribution network line;

[0043] Figure 3 This is the schematic diagram of the short-circuit fault in the K1 section;

[0044] Figure 4 This is a schematic diagram of the short-circuit fault in the K2 section;

[0045] Figure 5 It is a short circuit fault in the K3 section. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only part of the embodiments of the present invention, not all of them. Based on the spirit of the present invention, other embodiments obtained by ordinary technicians in this field without creative work are all within the scope of protection of the present invention.

[0047] In order to achieve effective coordination between outgoing line protection and section switch protection, the principle of distribution network line switch protection configuration must be unified to achieve orderly tripping of line switches. Since the tripping time of a general pole-mounted circuit breaker switch or ring network cabinet switch is about 150ms, the protection classification difference time should be at least not less than 0.2s to achieve effective coordination of the upper and lower switches in time.

[0048] like Figure 1 As shown, considering the case of a step difference of 0.2s: For 10kV lines outgoing from 110kV and 220kV substations, three levels of protection can be set in principle: the first level is divided into three sections of 0s, 0.5s, and 0.7-1.1s, which is realized by the outgoing line switch protection; the second level is divided into two sections of 0.3s and 0.5s, the second level I section is fully coordinated with the first level I section, and the second level II section is not fully coordinated with the first level II section; the third level is divided into two sections of 0s and 0.3s, which is fully coordinated with the second level protection. The first level switch overcurrent I section serves as the backup protection for the entire line.

[0049] The primary and secondary fusion magnetic circuit breaker has the ability to quickly open the gate, and the overall opening action time can be less than 60ms. The ability to quickly open the gate ensures that the hierarchical protection using the primary and secondary fusion magnetic circuit breaker can have more room for differential setting, and a smaller differential can be set - further making the coordination between the switches closer and the overall fault handling action faster. Taking into account the general configuration principle of the above-mentioned distribution network hierarchical protection, the differential is set according to the switch opening time of 150ms, and the opening time of the magnetic circuit breaker is less than 60ms. Therefore, the differential of the hierarchical protection technology implemented by the magnetic circuit breaker can be shortened by more than half of its typical value, the overall fault handling time is shortened, and the fault tolerance rate of the solution is higher.

[0050] The first embodiment of the present invention provides a distribution network hierarchical protection method based on the rapid opening and closing capability and post-acceleration function of a magnetically controlled switch, comprising:

[0051] Step 1: The magnetically controlled outgoing line switch is used as the first-level outgoing line protection, and overcurrent protection and voltage detection reclosing are configured. The overcurrent protection is divided into three stages: overcurrent stage I 0s, overcurrent stage II 0.4s, overcurrent stage III 0.6s, and voltage detection reclosing is set to 1 time with a delay of 2s.

[0052] Step 2: The magnetically controlled first section switch and the magnetically controlled second section switch are used as the second-level branch head-end protection, and the closing power supply fault detection accelerated opening delay and short-time power supply detection time opening and reverse locking are configured;

[0053] Parameter configuration for the first magnetically controlled section switch, including: 0.3s closing power detection fault acceleration trip delay (post-acceleration protection), less than 0.12s or more than 0.4s short-time power detection time trip and reverse locking, and combined with post-acceleration protection, set a 0.1s step difference and a 5s fault handling time window;

[0054] Parameter configuration of the second magnetically controlled section switch, including: 0.2s closing power detection fault acceleration opening delay (post-acceleration protection), 0.3s-0.4s short-time power detection time opening and reverse locking, and combined with post-acceleration protection, 0.1s step difference and 5s fault handling time window;

[0055] By setting a 0.1s difference in the opening delay protection and locking protection of the magnetically controlled first section switch and the magnetically controlled second section switch, the opening time window of different switches is shortened to within 0.1s. This enables orderly coordination between the switches while reducing the overall fault handling time, and can logically handle faults in different sections.

[0056] At present, the typical opening action time of general existing switches is 150ms. Only by utilizing the fast action characteristic of the magnetically controlled switch of less than 60ms can the step difference of 0.1s be set, thereby greatly shortening the overall fault handling time.

[0057] Step 3, the magnetically controlled contact switch is used as the third-level boundary protection, and parameter configuration is performed, including: setting the short-time power supply detection time to open the switch and reverse lock. If 0.2s < short-time power supply duration < 0.3s, reverse lock is performed and the timing is not started; if the short-time power supply time is not between 0.2s and 0.3s, delay closing, and short-time power supply within 5s of single-side voltage loss will restore power supply to the faulty back-end.

[0058] The three-level protection consists of outgoing line protection + branch head end protection + boundary protection, and a step difference of 0.2s is set between each level of the three-level protection.

[0059] As a prominent substantive feature of the present invention and one of the significant advances it brings to the prior art, the present invention focuses on utilizing the post-acceleration hierarchical protection of the full-line magnetically controlled switches to realize a fully automatic fault handling solution for the distribution network lines; and in the present invention, only the outgoing switch has an overcurrent protection outlet, and the section switches have no overcurrent protection outlets. Instead, the post-acceleration protection and its delay are configured according to the delay of the three-stage overcurrent protection of the outgoing switch. At the same time, the section switches and the connecting switches increase the short-time power supply time detection and reverse locking functions to cooperate with the post-acceleration protection function.

[0060] Step 4: If a short circuit fault occurs in the distribution network overhead line, the hierarchical protection magnetic control switch will be activated to complete the fault isolation.

[0061] In a preferred but non-limiting embodiment of the present invention, step 4 specifically comprises:

[0062] If a short circuit fault occurs at the incoming line end of the distribution network overhead line, after the fault occurs, the magnetically controlled outgoing line switch protection opens, and the magnetically controlled first section switch and the magnetically controlled second section switch remain in the closed state;

[0063] The magnetically controlled outgoing line switch will reclose after a delay of 2s. If it is a transient fault, it will return to normal;

[0064] If it is a permanent fault, the magnetically controlled outlet switch will open again for protection and will not reclose; the magnetically controlled first section switch detects that the short-term power duration is less than 0.12s (overcurrent section I 0s) or the short-term power duration of the overcurrent section II or overcurrent section III of the magnetically controlled outlet switch is greater than 0.4s, and it will automatically open and reverse lock, among which 0.12s is the minimum first section setting time and 0.4s is the maximum first section setting time; and if the short-term power duration is not within the setting time of 0.3~0.4s of the magnetically controlled second section switch, the magnetically controlled second section switch will remain closed.

[0065] After one side of the magnetically controlled contact switch loses voltage, a short-term power supply is detected and the duration is not within the set time of 0.2s to 0.3s, and the switch is closed with a delay to restore power supply to the faulty rear end.

[0066] If a short circuit fault occurs at the transmission end of the overhead line of the distribution network, the overcurrent II section or overcurrent III section protection of the magnetically controlled outgoing line switch will be opened, and the magnetically controlled first section switch and the magnetically controlled second section switch will remain in the closed state;

[0067] The magnetically controlled outgoing line switch will reclose after a delay of 2s. If it is a transient fault, it will return to normal;

[0068] If it is a permanent fault, the magnetically controlled first section switch will accelerate the protection opening delay of 0.3s and lock forward. The magnetically controlled outgoing line switch will not operate until the protection delay of 0.4s or 0.6s is reached. The magnetically controlled second section switch will automatically open and lock reversely if it detects that the short-term incoming call time is between 0.3s and 0.4s of the second section setting time.

[0069] After one side of the magnetically controlled contact switch loses voltage, if a short-term power supply is detected and the duration is not within the set time of 0.2s to 0.3s, the switch will be closed with a delay to restore power supply to the faulty rear end.

[0070] If a short circuit fault occurs at the end of the overhead line of the distribution network, the protection of section II or section III of the magnetically controlled outgoing line switch will be opened, and the magnetically controlled first section switch and the magnetically controlled second section switch will remain in the closed state;

[0071] The magnetically controlled outgoing line switch will reclose after a delay of 2s. If it is a transient fault, it will return to normal;

[0072] If it is a permanent fault, the magnetically controlled second section switch accelerates the protection to open (delay 0.2s) and positively locks. The magnetically controlled outgoing line switch does not operate before the set protection delay of 0.4s or 0.6s. The magnetically controlled first section switch does not operate before the set protection delay of 0.3s.

[0073] After one side of the magnetically controlled contact switch loses pressure, a short-term power supply is detected, but the duration is within the set time of 0.2s to 0.3s. The lockout delay will no longer close the switch and transfer power, thus completing the fault isolation.

[0074] As a prominent substantive feature of the present invention and one of the significant advances it brings to the prior art, a fully automatic fault handling solution for the distribution network is realized by relying on the post-acceleration hierarchical protection coordination of the magnetically controlled switches on the entire line. Moreover, since only the outgoing line switches are equipped with overcurrent protection outlets, the problem of simultaneous tripping of the same-layer protection is avoided. At the same time, based on the rapid separation and combination capabilities of the magnetically controlled switches, the hierarchical protection differential configuration margin is large, and the overall fault handling action speed is fast.

[0075] A second embodiment of the present invention provides a distribution network hierarchical protection system based on post-acceleration hierarchical protection of magnetically controlled switches, comprising:

[0076] Outgoing line protection module, used to configure overcurrent protection and voltage detection reclosing for magnetically controlled outgoing line switches;

[0077] Branch protection module, used to configure delay protection and locking protection for magnetically controlled section switches;

[0078] Boundary protection module, used to configure locking protection and transfer timing for magnetically controlled contact switches;

[0079] The protection module is used to complete fault isolation by actuating the graded protection magnetic control switch when a fault occurs at the incoming end of the distribution network overhead line.

[0080] The third embodiment of the present invention is as follows Figure 2 The distribution network line topology shown in the figure is used as an example to verify the hierarchical post-acceleration protection method of the present invention, wherein CB1 is the first outgoing line switch, CB2 is the first outgoing line switch, CB3 is the third outgoing line switch, CB4 is the fourth outgoing line switch, LS1 is the first connecting switch, LS2 is the second connecting switch, and LS3 is the third connecting switch. FB1 is the first section switch of the 10kV Ke line, FB2 is the second section switch of the 10kV Ke line, the overcurrent protection of the first section switch FB1 does not bypass CB1, and the overcurrent protection is limited to the outlet of the first outgoing line switch CB1, K1~K4 represent line sections, and the dotted line represents the omitted line section. The above switches are all equipped with magnetically controlled circuit breakers, and the switch parameter settings of their hierarchical protection are shown in Table 2-1.

[0081] Table 2-1 Configuration of three-level protection switches

[0082]

[0083] If it happens Figure 3 For the short-circuit fault of the K1 incoming line section shown, the hierarchical protection method is as follows:

[0084] After the fault occurs, the first outgoing line switch CB1 is protected and opened, and the first section switch FB1 of Ke-1 and the second section switch FB2 of Ke-1 remain closed;

[0085] The first outgoing line switch CB1 will reclose after a delay of 2s. If it is a transient fault, it will return to normal;

[0086] If it is a permanent fault, the first outgoing line switch CB1 will open again for protection and will not close again; the first section switch FB1 of Ke-1 line detects that the short-term power duration is less than 0.12s (overcurrent section I 0s) or the short-term power duration of overcurrent section II or section III is greater than 0.4s, and automatically opens and reverse locks, among which 0.4s is the minimum first section setting time and 0.12s is the maximum first section setting time; and the short-term power duration is not within the second section setting time of 0.3~0.4s, the second section switch FB2 of Ke-1 line remains closed.

[0087] After the first contact switch LS1 loses voltage on one side, it detects a short-term power supply and the duration is not within the set time of 0.2s to 0.3s, delays closing, and restores power supply to the faulty rear end.

[0088] If it happens Figure 4 The K2 transmission section short circuit fault shown in the figure has the following hierarchical protection method:

[0089] The first outgoing line switch CB1 is protected as open (Section II or Section III), and the first section switch FB1 of Ke-1 and the second section switch FB2 of Ke-1 remain in the closed state;

[0090] The first outgoing line switch CB1 will reclose after a delay of 2s. If it is a transient fault, it will return to normal;

[0091] If it is a permanent fault, the first section switch FB1 of the first line of the science and technology line will accelerate the protection to open the gate (delay 0.3s) and lock forward. The first outgoing line switch CB1 has not reached the protection delay of 0.4s or 0.6s, and the first outgoing line switch CBI will no longer operate; the second section switch FB2 of the science and technology line detects that the short-term power supply time is between the second section setting time of 0.3s and 0.4s, and automatically opens the gate and locks in the reverse direction;

[0092] After the first contact switch LS1 loses voltage on one side, it detects a short-term power supply and the duration is not within the set time of 0.2s to 0.3s, delays closing, and restores power supply to the faulty rear end.

[0093] If it happens Figure 5 For the short-circuit fault of the K3 terminal section shown, the hierarchical protection method is as follows:

[0094] The first outgoing line switch CB1 is protected as open (Section II or Section III), and the first section switch FB1 of the Ke-1 line and the second section switch FB2 of the Ke-1 line remain in the closed state;

[0095] The first outgoing line switch CB1 will reclose after a delay of 2s. If it is a transient fault, it will return to normal;

[0096] If it is a permanent fault, the second section switch FB2 of Ke Line 1 will accelerate the protection to open (delay 0.2s) and lock forward. The first outgoing line switch CB1 has not reached the set protection delay of 0.4s or 0.6s, and the first outgoing line switch CBI will not operate. The first section switch FB1 of Ke Line 1 has not reached the first section protection delay of 0.3s, and the first section switch of Ke Line 1 will not operate.

[0097] After the first contact switch LS1 loses pressure on one side, a short-term power supply is detected, but the duration is within the set time of 0.2s to 0.3s. The lockout delay is no longer closed and power is transferred, completing the fault isolation.

[0098] According to the above analysis, the shortest time for each switch to achieve coordination is only 60ms, and the hierarchical protection difference is configured accordingly, and the difference can be shortened to 0.1s. For fault handling, a short difference can be set in combination with post-acceleration protection to achieve rapid isolation and self-healing of the fault.

[0099] The present disclosure may be a system, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present disclosure.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A distribution network classification and acceleration protection method based on magnetically controlled switches, characterized in that: include: The magnetically controlled outgoing line switch is equipped with overcurrent protection and voltage detection reclosing switch as the first-level outgoing line protection; The first magnetically controlled section switch and the second magnetically controlled section switch are configured with a closing power supply fault detection acceleration opening delay and a short-time power supply detection time opening and reverse locking, as the second-level branch head end protection; The magnetically controlled contact switch is configured to detect the short-time power supply time, trip the switch, reversely lock, and start the power transfer timing, as the third-level boundary protection; If a short circuit occurs in the overhead line of the distribution network, a level difference is set between the three levels of protection, and the three-level protection magnetically controlled switches cooperate to accelerate the isolation of the fault.

2. A distribution network classification and acceleration protection method based on magnetically controlled switches as claimed in claim 1, characterized in that: For magnetically controlled outgoing line switches, overcurrent protection is divided into three stages: overcurrent stage I 0s, overcurrent stage II 0.4s, overcurrent stage III 0.6s, and the voltage detection reclosing is set to 1 time with a delay of 2s; For the first magnetically controlled section switch, a 0.3s closing power detection fault acceleration trip delay is set as post-acceleration protection; a short-time power detection time of less than 0.12s or greater than 0.4s is used to trip and reversely lock, and a 0.1s step difference is set in combination with post-acceleration protection; a 5s fault handling time window; For the magnetically controlled second section switch, a 0.2s closing power supply fault detection and accelerated opening delay is set as post-acceleration protection; a 0.3s-0.4s short-time power supply detection time is used for opening and reverse locking, and a 0.1s step difference is set in combination with the post-acceleration protection; a 5s fault handling time window.

3. A distribution network classification and acceleration protection method based on magnetically controlled switches as claimed in claim 2, characterized in that: For magnetically controlled contact switches, the short-time power supply time is set to open the switch and reverse lock. If 0.2s < the duration of the short-time power supply < 0.3s, the reverse lock is performed and the timing is not started. If the short-time power supply time is not between 0.2s and 0.3s, the closing time is delayed to restore the power supply to the faulty back-end.

4. The method for accelerating protection of distribution network after classification based on magnetically controlled switches according to claim 1, characterized in that: When a short circuit occurs at the incoming end of the distribution network overhead line, the hierarchical protection magnetic control switch action is as follows: After a fault occurs, the magnetically controlled outgoing line switch is protected to open, and the magnetically controlled first section switch and the magnetically controlled second section switch remain in the closed state; The magnetically controlled outgoing line switch will reclose after a delay of 2s. If it is a momentary fault, it will return to normal.

5. A distribution network post-grading acceleration protection method based on magnetically controlled switches as claimed in claim 4, characterized in that: If it is a permanent fault, the magnetically controlled outlet switch will open again for protection and will not reclose; the magnetically controlled first section switch will automatically open and reversely lock when it detects that the short-term power duration is less than 0.12s or the short-term power duration of the overcurrent section II or overcurrent section III of the magnetically controlled outlet switch is greater than 0.4s, where 0.12s is the minimum first section setting time and 0.4s is the maximum first section setting time; and if the short-term power duration is not within the setting time of 0.3 to 0.4s of the magnetically controlled second section switch, the magnetically controlled second section switch will remain closed; After one side of the magnetically controlled contact switch loses voltage, a short-term power supply is detected and the duration is not within the set time of 0.2s to 0.3s, and the switch is closed with a delay to restore power supply to the faulty rear end.

6. The method for accelerating protection of distribution network after classification based on magnetically controlled switches according to claim 1, characterized in that: When a short circuit occurs at the transmission end of the overhead line of the distribution network, the actions of the graded protection magnetic control switch are as follows: The magnetically controlled outlet switch is opened for overcurrent section II or overcurrent section III protection, and the magnetically controlled first section switch and the magnetically controlled second section switch remain in the closed state; The magnetically controlled outgoing line switch will reclose after a delay of 2s. If it is a momentary fault, it will return to normal.

7. A distribution network classification and acceleration protection method based on magnetically controlled switches as claimed in claim 6, characterized in that: If it is a permanent fault, the magnetically controlled first section switch will accelerate the protection opening delay of 0.3s and lock forward. The magnetically controlled outgoing line switch will not operate until the protection delay of 0.4s or 0.6s is reached. The magnetically controlled second section switch will automatically open and lock reversely if it detects that the short-term incoming call time is between 0.3s and 0.4s of the second section setting time. After one side of the magnetically controlled contact switch loses voltage, a short-term power supply is detected and the duration is not within the set time of 0.2s to 0.3s, and the switch is closed with a delay to restore power supply to the faulty rear end.

8. The method for accelerating protection of distribution network after classification based on magnetically controlled switches according to claim 1, characterized in that: When a short circuit occurs at the end of the distribution network overhead line, the hierarchical protection magnetic control switch action is as follows: The protection of section II or section III of the magnetically controlled outgoing line switch is opened, and the magnetically controlled first section switch and the magnetically controlled second section switch remain in the closed state; The magnetically controlled outgoing line switch will reclose after a delay of 2s. If it is a transient fault, it will return to normal; If it is a permanent fault, the acceleration protection tripping delay of the second section switch of the magnetic control is 0.2s and positively locked. The magnetic control outgoing line switch does not operate before the set protection delay of 0.4s or 0.6s. The magnetic control first section switch does not operate before the first section protection delay of 0.3s. After one side of the magnetically controlled contact switch loses pressure, a short-term power supply is detected, but the duration is within the set time of 0.2s to 0.3s. The lockout delay will no longer close the switch and transfer power, thus completing the fault isolation.

9. A distribution network classification and acceleration protection method based on magnetically controlled switches as claimed in claim 8, characterized in that: The magnetically controlled outgoing line switch, the magnetically controlled first section switch, the magnetically controlled second section switch and the magnetically controlled connecting switch are all equipped with magnetically controlled circuit breakers.

10. A distribution network classification post-acceleration protection system based on magnetically controlled switches, running a distribution network classification post-acceleration protection method based on magnetically controlled switches as described in any one of claims 1 to 9, characterized in that: include: Outgoing line protection module, used to configure overcurrent protection and voltage detection reclosing for magnetically controlled outgoing line switches; Branch protection module, used to configure delay protection and locking protection for magnetically controlled section switches; Boundary protection module, used to configure locking protection and transfer timing for magnetically controlled contact switches; The protection module is used to complete fault isolation by actuating the graded protection magnetic control switch when a fault occurs at the incoming end of the distribution network overhead line.

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