Protection and Control Method and Device for Distribution Lines

Abstract

The present invention discloses a protection control method and device for a distribution line. Wherein, the method includes: determining a faulty distribution line and the line type corresponding to the faulty distribution line; when it is determined that the line type is a ring network line, acquiring a first monitored current corresponding to the faulty distribution line; judging whether the first monitored current meets a first preset current condition to obtain a first judgment result; and determining a protection action strategy for the faulty distribution line according to the first judgment result. The present invention solves the technical problem that the protection action determination of the distribution line in the related art is inaccurate, resulting in the inability to effectively ensure the safe and stable operation of the power network.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution line protection, and in particular, to a protection control method and device for a distribution line. Background Art

[0002] For the power supply reliability and economy of an AC-DC hybrid distribution network, a complete and effective relay protection scheme for the AC-DC hybrid distribution network is particularly important. Currently, there are multiple relay protection schemes for the AC-DC hybrid distribution network, and different relay protection devices correspond to different action strategies. However, the action determination method of the relay protection device in the prior art cannot make an accurate judgment in some cases, which easily causes misoperation of the relay protection device, thereby affecting the normal and safe operation of the AC-DC hybrid distribution network.

[0003] In view of the above problems, no effective solution has been proposed yet. Summary of the Invention

[0004] Embodiments of the present invention provide a protection control method and device for a distribution line, so as to at least solve the technical problem that the protection action determination of the distribution line in the related art is inaccurate, resulting in the inability to effectively guarantee the safe and stable operation of the power network.

[0005] According to one aspect of the embodiments of the present invention, a protection control method for a distribution line is provided, including: determining a faulty distribution line and the line type corresponding to the faulty distribution line; in the case where the determined line type is a ring network line, obtaining a first monitored current corresponding to the faulty distribution line; judging whether the first monitored current meets a first preset current condition to obtain a first judgment result; and determining a protection action strategy for the faulty distribution line according to the first judgment result.

[0006] Optionally, when the first monitored current includes the differential current, the change in differential current, and the zero-sequence differential current of the distribution line, and the first preset current condition includes a second preset current condition, the judging whether the first monitored current meets the first preset current condition to obtain a first judgment result includes: judging whether the differential current, the change in differential current, and the zero-sequence differential current meet the second preset current condition to obtain the first judgment result; and the determining a protection action strategy for the faulty distribution line according to the first judgment result includes: if the first judgment result indicates that at least one of the differential current, the change in differential current, and the zero-sequence differential current meets the second preset current condition, determining the protection action strategy as: controlling to start differential protection for the faulty distribution line, where starting the differential protection includes at least one of the following: the steady-state quantity differential action element corresponding to the faulty distribution line acts, the change quantity differential action element acts, and the zero-sequence current differential action element acts.

[0007] Optionally, when the second preset current condition includes a first sub-preset current condition, determining whether the first monitored current meets the first preset current condition to obtain a first determination result includes: determining whether the differential current meets the first sub-preset current condition to obtain the first determination result; determining the protection action strategy for the faulty distribution line according to the first determination result includes: if the first determination result indicates that the differential current meets the first sub-preset current condition, determining the protection action strategy as: controlling the steady-state quantity differential action element corresponding to the faulty distribution line to act.

[0008] Optionally, when the second preset current condition includes a second sub-preset current condition, determining whether the first monitored current meets the first preset current condition to obtain a first determination result includes: determining whether the change amount of the differential current meets the second sub-preset current condition to obtain the first determination result; determining the protection action strategy for the faulty distribution line according to the first determination result includes: if the first determination result indicates that the change amount of the differential current meets the second sub-preset current condition, determining the protection action strategy as: controlling the change amount differential action element corresponding to the faulty distribution line to act.

[0009] Optionally, when the second preset current condition includes a third sub-preset current condition, determining whether the first monitored current meets the first preset current condition to obtain a first determination result includes: determining whether the zero-sequence differential current meets the third sub-preset current condition to obtain the first determination result; determining the protection action strategy for the faulty distribution line according to the first determination result includes: if the first determination result indicates that the zero-sequence differential current meets the third sub-preset current condition, determining the protection action strategy as: controlling the zero-sequence current differential action element corresponding to the faulty distribution line to act.

[0010] Optionally, when the first monitored current includes the phase current of the distribution line and the first preset current condition includes a third preset current condition, determining whether the first monitored current meets the first preset current condition to obtain a first determination result includes: determining whether the phase current meets the third preset current condition to obtain the first determination result; determining the protection action strategy for the faulty distribution line according to the first determination result includes: if the first determination result indicates that the phase current meets the third preset current condition, determining the protection action strategy as: controlling the negative pressure blocking overcurrent protection to be started for the faulty distribution line.

[0011] Optionally, when the first monitored current includes the zero-sequence current of the above distribution line and the above first preset current condition includes the fourth preset current condition, determining whether the first monitored current meets the first preset current condition to obtain a first judgment result includes: determining whether the zero-sequence current meets the fourth preset current condition to obtain the first judgment result; determining the protection action strategy for the faulty distribution line according to the first judgment result includes: if the first judgment result indicates that the zero-sequence current meets the fourth preset current condition, determining the protection action strategy as: controlling to initiate zero-sequence overcurrent protection for the faulty distribution line.

[0012] Optionally, when the first monitored current includes the maximum phase current of the above distribution line and the above first preset current condition includes the fifth preset current condition, determining whether the first monitored current meets the first preset current condition to obtain a first judgment result includes: determining whether the maximum phase current meets the fifth preset current condition to obtain the first judgment result; determining the protection action strategy for the faulty distribution line according to the first judgment result includes: if the first judgment result indicates that the maximum phase current meets the fifth preset current condition, determining the protection action strategy as: controlling to initiate overcurrent acceleration protection for the faulty distribution line.

[0013] Optionally, when the first monitored current includes the zero-sequence current of the above distribution line and the above first preset current condition includes the sixth preset current condition, determining whether the first monitored current meets the first preset current condition to obtain a first judgment result includes: determining whether the zero-sequence current meets the sixth preset current condition to obtain the first judgment result; determining the protection action strategy for the faulty distribution line according to the first judgment result includes: if the first judgment result indicates that the zero-sequence current meets the sixth preset current condition, determining the protection action strategy as: controlling to initiate zero-sequence overcurrent acceleration protection for the faulty distribution line.

[0014] Optionally, when it is determined that the line type is a feeder line, obtain the second monitored current corresponding to the faulty distribution line, where the second monitored current at least includes: the maximum phase current; determine whether the second monitored current meets the seventh preset current condition to obtain a second judgment result; if the second judgment result indicates that the second monitored current meets the seventh preset current condition, determine the protection action strategy for the faulty distribution line as: controlling to initiate overcurrent protection for the phase with voltage transformer disconnection for the faulty distribution line.

[0015] Optionally, determine whether the differential protection device corresponding to the faulty power distribution line operates; if the differential protection device corresponding to the faulty power distribution line does not operate, obtain the differential protection device corresponding to the neighboring power distribution line of the faulty power distribution line; based on the above protection action strategy, control the differential protection device corresponding to the neighboring power distribution line to operate.

[0016] According to another aspect of the embodiments of the present invention, there is also provided a protection control device for a power distribution line, including: a first determination module, configured to determine a faulty power distribution line and the line type corresponding to the faulty power distribution line; an acquisition module, configured to, when determining that the line type is a ring network line, acquire a first monitored current corresponding to the faulty power distribution line; a judgment module, configured to judge whether the first monitored current meets a first preset current condition to obtain a first judgment result; a second determination module, configured to determine a protection action strategy for the faulty power distribution line according to the first judgment result.

[0017] In the embodiments of the present invention, by determining a faulty power distribution line and the line type corresponding to the faulty power distribution line; when determining that the line type is a ring network line, acquiring a first monitored current corresponding to the faulty power distribution line; judging whether the first monitored current meets a first preset current condition to obtain a first judgment result; and determining a protection action strategy for the faulty power distribution line according to the first judgment result, the purpose of accurately determining the protection action strategy of the power distribution line according to the type of the power distribution line and the monitored current is achieved, thereby realizing the technical effect of improving the accuracy of the protection action of the power distribution line, and further effectively ensuring the safe and stable operation of the power grid, and further solving the technical problem that the protection action determination of the power distribution line in the related art is inaccurate, resulting in the inability to effectively ensure the safe and stable operation of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the present invention, and constitute a part of this application. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation to the present invention. In the drawings:

[0019] Figure 1 is a flowchart of a protection control method for a power distribution line according to an embodiment of the present invention;

[0020] Figure 2 is an optional power distribution network topology diagram according to an embodiment of the present invention;

[0021] Figure 3 is a flowchart of an optional pilot differential protection for a power distribution line according to an embodiment of the present invention;

[0022] Figure 4It is a schematic diagram of the operation of an optional overcurrent protection direction element according to an embodiment of the present invention;

[0023] Figure 5 It is a flowchart of an optional negative pressure locked overcurrent protection according to an embodiment of the present invention;

[0024] Figure 6 It is a flowchart of an optional zero-sequence overcurrent protection according to an embodiment of the present invention;

[0025] Figure 7 It is a flowchart of an optional overcurrent acceleration protection according to an embodiment of the present invention;

[0026] Figure 8 It is a flowchart of an optional zero-sequence overcurrent acceleration section protection according to an embodiment of the present invention;

[0027] Figure 9 It is a flowchart of an optional overcurrent protection for the broken phase of a voltage transformer according to an embodiment of the present invention;

[0028] Figure 10 It is a flowchart of an optional overload alarm according to an embodiment of the present invention;

[0029] Figure 11 It is an optional distribution network topology diagram according to an embodiment of the present invention;

[0030] Figure 12 It is a schematic diagram of the structure of a protection control device for a distribution line according to an embodiment of the present invention. Specific embodiments

[0031] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0032] It should be noted that the terms "first", "second", etc. in the description, claims and above-mentioned drawings of the present invention are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0033] According to an embodiment of the present invention, an embodiment of a method for protecting and controlling a distribution line is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. And although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that here.

[0034] Figure 1 is a flowchart of a method for protecting and controlling a distribution line according to an embodiment of the present invention, as Figure 1 shown, the method includes the following steps:

[0035] Step S102, determine the faulty distribution line and the line type corresponding to the faulty distribution line;

[0036] Step S104, when it is determined that the line type is a ring network line, obtain the first monitored current corresponding to the faulty distribution line;

[0037] Step S106, determine whether the first monitored current meets the first preset current condition to obtain a first judgment result;

[0038] Step S108, determine the protection action strategy for the faulty distribution line according to the first judgment result.

[0039] Optionally, the above line type can be but is not limited to a ring network line, a feeder line, etc.

[0040] Optionally, when a fault occurs in the line type, different monitored currents are obtained correspondingly, and then the protection action strategies applicable to different line types are determined.

[0041] Optionally, when the line type of the faulty power distribution line is a ring network line, the first monitoring current corresponding to the ring network circuit is obtained, and the corresponding protection action strategy is determined according to the first monitoring current. The above protection action strategy may include, but is not limited to, at least one of the following: controlling the start of differential protection for the above faulty power distribution line, controlling the start of negative voltage locked overcurrent protection for the above faulty power distribution line, controlling the start of negative voltage locked overcurrent protection for the above faulty power distribution line, controlling the start of zero-sequence overcurrent protection for the above faulty power distribution line, controlling the start of overcurrent acceleration protection for the above faulty power distribution line, and controlling the start of zero-sequence overcurrent acceleration protection for the above faulty power distribution line.

[0042] Optionally, the above first monitoring current may be multiple monitoring currents, including, but not limited to: differential current, differential current change, zero-sequence differential current, etc. Different protection action strategies correspond to different above first monitoring currents and different preset current conditions. That is, when any one of the multiple monitoring currents meets the preset current condition, the protection action strategy corresponding to the above any one monitoring current is started correspondingly.

[0043] Optionally, when the line type of the faulty power distribution line is a feeder line, the second monitoring current corresponding to the feeder circuit is obtained, and the corresponding protection action strategy is determined according to the second monitoring current. The above protection action strategy may be, but is not limited to: controlling the start of overcurrent protection for the phase with voltage transformer disconnection for the above faulty power distribution line.

[0044] In the embodiment of the present invention, by determining the faulty power distribution line and the line type corresponding to the above faulty power distribution line; when determining that the above line type is a ring network line, obtaining the first monitoring current corresponding to the above faulty power distribution line; judging whether the above first monitoring current meets the first preset current condition to obtain a first judgment result; and determining the protection action strategy of the above faulty power distribution line according to the above first judgment result, the purpose of accurately determining the protection action strategy of the power distribution line according to the type of the power distribution line and the monitoring current is achieved, thereby realizing the improvement of the accuracy of the protection action of the power distribution line, and further effectively ensuring the safe and stable operation of the power network. Furthermore, the technical problem that the power network cannot be effectively guaranteed to operate safely and stably due to inaccurate determination of the protection action of the power distribution line in the related art is solved.

[0045] Optionally, the above steps S102 to S108 belong to the local protection of the power distribution line and may be applied, but are not limited to, to an Figure 2 AC system as shown, where multiple ring-in and ring-out switch stations are connected in series in the AC system to form a "hand-in-hand" series power supply loop, as Figure 2As shown in the figure. When the power grid is operating normally, there is only one switch in the power supply loop operating in an open-loop manner. In the target grid framework, the local protection of the AC system is mainly based on the intelligent distributed distribution network automation terminal DTU that integrates the primary and secondary functions. The optical fiber differential protection is locally configured as the main protection for each section, and with the local self-healing scheme, it has the ability to accurately locate faults and self-heal.

[0046] In this AC system, interval distribution network automation terminals DTU are configured for the "hand-in-hand" line switches to achieve line optical fiber pilot differential protection, directional overcurrent protection, loop closing protection, malfunction protection, and local self-healing; interval distribution network automation terminals DTU are configured for the outgoing line switches of the switch station to achieve directional overcurrent instantaneous protection. A common DTU is configured to complete the information interaction function between all interval DTUs of the switch station and the distribution automation main station system. The data and information of all interval DTUs are sent to the distribution automation main station through the switch via the common DTU. Specifically, corresponding protection functions can be configured according to different fault types.

[0047] For example, for the ring network line, the following can be configured: (1) Optical fiber pilot differential protection: Configure optical fiber pilot differential protection reflecting short-circuit faults and zero-sequence differential protection for grounding faults as the main protection for the incoming and outgoing ring lines of the switch station, and communicate and exchange data with the substation outgoing line protection and the incoming and outgoing ring line protection of the opposite switch cabinet to complete the current differential protection function. (2) Overcurrent (directional) protection: Configure directional overcurrent protection and zero-sequence overcurrent as the backup protection for the incoming and outgoing lines, busbars, and outgoing lines of the switch station. (3) Loop closing protection: When the incoming and outgoing line switches and tie switches of the switch station are closed to two power sources, the loop closing protection function is started. When the loop closing conditions are not met, it can act reliably to prevent the expansion of accidents. (4) Malfunction protection: Reflect the malfunction of the incoming and outgoing ring line switches, tie switches, and outgoing line switches of the switch station, and trip all the switches on the bus where the switch is located. (5) Local self-healing: Realize the backup power supply automatic switching function of the incoming and outgoing line switches in the switch station. When the bus loses power and the transfer conditions are met, the tie switch is put into operation to realize load transfer. For the outgoing line, overcurrent (directional) instantaneous protection can be configured: Configure directional overcurrent instantaneous protection as the main protection for the outgoing line. In addition, it has measurement and control functions, including remote measurement, remote signaling, and remote control functions.

[0048] In an alternative embodiment, when the first monitored current includes the differential current, differential current change amount, and zero-sequence differential current of the above-mentioned distribution line, and the above-mentioned first preset current condition includes the second preset current condition, the above-mentioned determining whether the first monitored current meets the first preset current condition to obtain a first judgment result includes: determining whether the differential current, the differential current change amount, and the zero-sequence differential current meet the above-mentioned second preset current condition to obtain the above-mentioned first judgment result;

[0049] Determining the protection action strategy for the faulty distribution line according to the above first judgment result includes: if the first judgment result indicates that at least one of the differential current, the change in differential current, and the zero-sequence differential current satisfies the second preset current condition, then determine the protection action strategy as: controlling the initiation of differential protection for the faulty distribution line.

[0050] Optionally, the initiation of differential protection includes at least one of the following: the steady-state quantity differential action element corresponding to the faulty distribution line operates, the change-in-quantity differential action element operates, and the zero-sequence current differential action element operates. It can be understood that only the action determination of the action element is mentioned in the above initiation of differential protection. Before determining the action of the action element, it is also necessary to determine the action of the starting element. That is, whether the current corresponding to the starting element satisfies the corresponding preset current condition. The above starting element can include, but is not limited to, a change-in-current starting element, a differential starting element, and an auxiliary voltage starting element.

[0051] Optionally, the change-in-current starting element detects the change in the instantaneous value of the current sampling in real time and is the main starting element of the pilot current differential protection. The corresponding preset current condition can include, but is not limited to:

[0052] ΔI φmax >1.25ΔI T +ΔI dz

[0053] Where: △I φmax is the change in phase current corresponding to the faulty distribution line; △ IT is the floating threshold, which gradually increases automatically as the output of the change in phase current increases. Taking 1.25 times can ensure that the threshold current is always slightly higher than the unbalanced output; △ Idz is the setting value of the change-in-current starting current.

[0054] Optionally, the above differential starting element includes a phase-difference differential starting element and a zero-sequence differential starting element. The differential starting element is triggered as soon as either of the two elements starts. The phase-difference differential starting element has high sensitivity in the case of a weak power source or a high-resistance fault on one side. Among them, the phase-difference differential starting element discriminates that the phase difference current of each phase is greater than 0.8 times the differential action current setting value, and the auxiliary voltage starting element operates. The corresponding preset current condition can include, but is not limited to: I CDφ >0.8I set . In the formula, I CDφ is the phase-difference differential current, and I set is the differential action current setting value.

[0055] The zero-sequence differential starting element is used to discriminate that the zero-sequence differential current is greater than 0.8 times the differential action current setting value, and the zero-sequence currents on both sides of the zero-sequence differential starting element are greater than the zero-sequence current starting setting value. The corresponding preset current condition can include, but is not limited to: 3I0 > 0.8I set 。Wherein, 3I 0 is the zero-sequence differential current, and Iset is the fixed value of the differential operating current.

[0056] Optionally, the auxiliary voltage starting element operates when any line voltage corresponding to the faulty distribution line is less than 60V or the change amount of any line voltage is greater than 8V.

[0057] In an optional embodiment, when the second preset current condition includes the first sub-preset current condition, determining whether the first monitored current satisfies the first preset current condition to obtain a first determination result includes: determining whether the differential current satisfies the first sub-preset current condition to obtain the first determination result;

[0058] Determining the protection action strategy for the faulty distribution line according to the first determination result includes: if the first determination result indicates that the differential current satisfies the first sub-preset current condition, determining the protection action strategy as: controlling the steady-state quantity differential operating element corresponding to the faulty distribution line to operate.

[0059] Optionally, the steady-state quantity differential operating element may but is not limited to be composed of two parts: a fast-section differential relay and a fast-section differential relay. The fast-section differential relay and the fast-section differential relay correspond to different preset current conditions.

[0060] Optionally, the fourth sub-preset current condition corresponding to the fast-section differential relay may be:

[0061] I CDΦ > I H

[0062] I CDΦ > 0.8I r

[0063] Wherein, I CDΦ = |I MΦ + I NΦ |, the differential current, is the amplitude of the vector sum of the two-side currents; I r = |I MΦ - I NΦ |, is the braking current, which is the amplitude of the vector difference of the two-side currents of the faulty distribution line; I H is 1.8 times the fixed value of the differential operating current.

[0064] Optionally, the fourth sub-preset current condition corresponding to the time-delay section differential relay may be:

[0065] I CDΦ > I SETΦ

[0066] I CDΦ > 0.75I r

[0067] Wherein, I CDΦ = |I MΦ + I NΦ | is the differential current, which is the magnitude of the vector sum of the currents on both sides of the faulty distribution line; I r = |I MΦ - I NΦ |, is the restraining current, which is the magnitude of the vector difference of the currents on both sides of the faulty distribution line; I SETφ is the fixed value of the differential operating current; the time-delayed differential relay is fixed to operate after a 25 ms delay.

[0068] In an optional embodiment, when the above second preset current condition includes a second sub-preset current condition, the above determining whether the first monitored current satisfies the first preset current condition to obtain a first determination result includes: determining whether the change amount of the differential current satisfies the second sub-preset current condition to obtain the first determination result;

[0069] The above determining the protection action strategy of the faulty distribution line according to the first determination result includes: if the first determination result indicates that the change amount of the differential current satisfies the second sub-preset current condition, then determining the protection action strategy as: controlling the change amount differential operating element corresponding to the faulty distribution line to operate.

[0070] Optionally, the change amount differential operating element is not affected by the line load and has high sensitivity in the case of high-resistance faults and oscillatory faults in the zone. The corresponding second sub-preset current condition may be:

[0071] ΔI CDΦ > I SETΦ

[0072] ΔI CDΦ > 0.75ΔI r

[0073] Wherein: ΔI CDΦ = |ΔI MΦ + ΔI NΦ |, is the change amount of the differential current, which is the magnitude of the vector sum of the change amounts of the currents on both sides of the faulty distribution line; ΔI r = |ΔI MΦ - ΔI NΦ |, is the change amount of the restraining current, which is the magnitude of the vector difference of the change amounts of the currents on both sides of the faulty distribution line; I SETφ is the fixed value of the differential operating current.

[0074] Optionally, the above-mentioned variable differential operating element is not put into use by default, and the usage of the above-mentioned variable differential operating element can be preset.

[0075] In an optional embodiment, when the above-mentioned second preset current condition includes a third sub-preset current condition, determining whether the above-mentioned first monitored current satisfies the first preset current condition to obtain a first judgment result includes: determining whether the zero-sequence differential current satisfies the above-mentioned third sub-preset current condition to obtain the above-mentioned first judgment result;

[0076] Determining the protection action strategy for the faulty distribution line according to the above-mentioned first judgment result includes: if the first judgment result indicates that the zero-sequence differential current satisfies the above-mentioned third sub-preset current condition, determining the protection action strategy as: controlling the zero-sequence current differential operating element corresponding to the faulty distribution line to act.

[0077] Optionally, the zero-sequence current differential operating element has high sensitivity when a single-phase grounding fault occurs in a small-resistance grounding system. The zero-sequence current differential operating element is fixed to act with a 100ms delay. When a current transformer CT breaks, the zero-sequence current differential operating element is blocked. When a two-phase or three-phase grounding fault occurs and the device determines that any two-phase currents on either side are greater than 2 times the rated value, the zero-sequence current differential operating element is blocked. The corresponding second sub-preset current condition can be:

[0078] I CD0 >I SETΦ

[0079] I CD0 >0.75I r0

[0080] Wherein, I CD0 =|3I M0 +3I N0 |, is the zero-sequence differential current, which is the amplitude of the vector sum of the zero-sequence currents on both sides of the faulty distribution line; I r0 =|3I M0 -3I N0 |, is the zero-sequence braking current, which is the amplitude of the vector difference of the zero-sequence currents on both sides of the faulty distribution line; I SETΦ is the differential operating current setting value.

[0081] It should be noted that when an out-of-zone fault occurs at the corresponding position of the faulty distribution line, the current transformer CT may be transiently saturated. To prevent the pilot current differential protection from malfunctioning, it can but is not limited to adopt a combination of a time-difference method for quickly identifying the in-zone and out-of-zone and a virtual braking current transformer saturation identification and opening element to ensure that the differential protection will not malfunction under relatively severe transient saturation conditions.

[0082] As an alternative embodiment, Figure 3 is a flowchart of an alternative pilot differential protection for a distribution line according to an embodiment of the present invention. As shown in Figure 3 When the pilot differential protection devices corresponding to both sides of the distribution line are in use, the optical fiber pilot channel is normal, and the pilot differential protection is started, when any corresponding phase difference relay, phase increment difference relay, and zero-sequence differential relay of the distribution line meet the preset current conditions, the corresponding pilot differential protection action is started.

[0083] It should be noted that the differential input includes soft and hard pressure plates and control words. When both are input, it is considered that the protection is input; when the differential setting of one side device of the faulty distribution line is input and the differential of the other side device is not input, an alarm of "differential input and output inconsistency" is reported. In addition, abnormal channel data includes high error code, connection error (device cross-connection), channel interruption, self-loop state inconsistent with setting, and out-of-step of both sides.

[0084] In an alternative embodiment, when the first monitored current includes the phase current of the above distribution line and the first preset current condition includes the third preset current condition, determining whether the first monitored current meets the first preset current condition to obtain a first judgment result includes: determining whether the phase current meets the third preset current condition to obtain the first judgment result;

[0085] Determining the protection action strategy for the faulty distribution line according to the first judgment result includes: if the first judgment result indicates that the phase current meets the third preset current condition, determining the protection action strategy as: controlling the start of negative voltage locked overcurrent protection for the faulty distribution line.

[0086] Optionally, the negative voltage locked overcurrent protection can be configured with multiple sections of protection, for example, configured with I to III sections of protection, which can be input and output through control words respectively. Configuring overcurrent I to III sections of protection can be input and output through control words respectively. The overcurrent elements are installed by phase, and whether to be blocked by complex voltage and direction can be selected by the control words "overcurrent n section through voltage" and "overcurrent n section through direction" (n = I, II, III). When the PT of the busbar current transformer is disconnected, the overcurrent protection with voltage or direction function will automatically withdraw. The corresponding third preset current condition is:

[0087] I Φ >I setn

[0088] where I Φ is the phase current, I setnIt is the setting value of the nth segment of overcurrent, where X = A, B, C. Among them, the directions of the above-mentioned three phases A, B, and C satisfy the following direction conditions: The direction element adopts 90° wiring and starts by phase. To eliminate the dead zone, the direction element has a memory function. The maximum sensitive angle of operation is fixed at -30°, the operation range is 150°, and the error is less than ±3°. Figure 4 It is a schematic diagram of the operation of an optional overcurrent protection direction element according to an embodiment of the present invention. Among them, the shaded part represents the operation area. The corresponding complex voltage opening of the above-mentioned negative voltage locked overcurrent protection satisfies the following complex voltage opening conditions: When any line voltage value of the faulty distribution line is lower than the overcurrent low voltage setting value or the negative sequence voltage is greater than the overcurrent negative sequence voltage setting value, the overcurrent protection is opened; otherwise, the overcurrent protection is locked.

[0089] As an optional embodiment, Figure 5 It is a flowchart of an optional negative voltage locked overcurrent protection according to an embodiment of the present invention. As Figure 5 shown, the method includes: When the nth segment of overcurrent protection in the distribution line is put into operation, and the nth segment of overcurrent is voltage-input and satisfies the complex voltage opening conditions, if any phase of the target distribution line satisfies the third preset current condition and the direction condition, then control to start the negative voltage locked overcurrent protection for the above-mentioned faulty distribution line, and the corresponding nth segment of overcurrent protection operates.

[0090] In an optional embodiment, when the first monitored current includes the zero-sequence current of the above-mentioned distribution line and the above-mentioned first preset current condition includes the fourth preset current condition, the determination of whether the first monitored current satisfies the first preset current condition to obtain the first determination result includes: Determining whether the zero-sequence current satisfies the above-mentioned fourth preset current condition to obtain the above-mentioned first determination result;

[0091] The determination of the protection operation strategy for the above-mentioned faulty distribution line according to the above-mentioned first determination result includes: If the first determination result indicates that the zero-sequence current satisfies the above-mentioned fourth preset current condition, then determine the protection operation strategy as: Control to start the zero-sequence overcurrent protection for the above-mentioned faulty distribution line.

[0092] Optionally, the above-mentioned zero-sequence overcurrent protection can be a pre-configured multi-segment zero-sequence overcurrent protection, such as two-segment zero-sequence overcurrent protection (I segment and II segment), which can be put into or taken out of operation through a control word respectively. The corresponding fourth preset current condition (i.e., the zero-sequence overcurrent nth segment current condition) can be expressed as:

[0093] I 0 >I setn

[0094] In the formula, I 0 is the self-produced or externally connected zero-sequence current, and I setnIt is the setting value of the nth segment of zero-sequence overcurrent, where n = I, II; the zero-sequence current is input using the self-produced zero-sequence current: the zero-sequence current is input using the control word of the self-produced zero-sequence current.

[0095] Optionally, in addition to satisfying the above fourth preset current condition (i.e., the zero-sequence overcurrent nth segment current condition), the zero-sequence overcurrent protection action criterion also needs to satisfy: the zero-sequence overcurrent nth segment is input.

[0096] As an optional embodiment, Figure 6 It is a flowchart of an optional zero-sequence overcurrent protection according to an embodiment of the present invention. As Figure 6 shown, the warning function of the second segment of zero-sequence overcurrent can be input through the control word "zero-sequence overcurrent warning", and the zero-sequence overcurrent warning function shares the setting value and delay of the second segment of zero-sequence overcurrent. Whether to select the self-produced or external zero-sequence current can be selected through the control word "the zero-sequence current uses the self-produced zero-sequence current"; when the self-produced zero-sequence current is used for the zero-sequence current, the current transformer CT disconnection warning locks the zero-sequence current action and warning.

[0097] In an optional embodiment, when the first monitored current includes the maximum phase current of the above distribution line and the above first preset current condition includes the fifth preset current condition, the above determination of whether the first monitored current satisfies the first preset current condition to obtain a first determination result includes: determining whether the maximum phase current satisfies the above fifth preset current condition to obtain the above first determination result;

[0098] The above determination of the protection action strategy for the faulty distribution line according to the above first determination result includes: if the first determination result indicates that the maximum phase current satisfies the above fifth preset current condition, then determine the above protection action strategy as: controlling the start of overcurrent acceleration protection for the above faulty distribution line.

[0099] Optionally, the overcurrent acceleration protection can be configured to be switched on and off through a control word. When manual closing or reclosing actions occur, the overcurrent acceleration protection is instantaneously input and returns after 3 s; the overcurrent acceleration protection can be selected whether to be blocked by voltage through the control word "overcurrent acceleration through voltage". If the bus voltage transformer PT is disconnected when the overcurrent acceleration through voltage is input, the overcurrent acceleration protection is automatically withdrawn. The corresponding fifth preset current condition (overcurrent acceleration segment current condition) can be expressed as:

[0100] I max >I set

[0101] In the formula, I max is the maximum phase current corresponding to the faulty distribution line, and I set is the setting value of the overcurrent acceleration segment corresponding to the faulty distribution line.

[0102] Optionally, Figure 7It is a flowchart of an optional overcurrent acceleration protection according to an embodiment of the present invention. As Figure 7 shown, for the above-mentioned overcurrent acceleration protection action criterion, in addition to satisfying the above five preset current conditions (overcurrent acceleration section current conditions), it is also necessary to simultaneously satisfy: the overcurrent acceleration section is put into operation, that is, the overcurrent acceleration protection control word is put into operation; the acceleration condition is satisfied: manual closing or reclosing action; the complex voltage opening is satisfied: in the case where the complex voltage opening in the overcurrent protection is satisfied, after a preset overcurrent acceleration section time, control the start of the overcurrent acceleration protection for the above-mentioned faulty distribution line.

[0103] In an optional embodiment, when the first monitored current includes the zero-sequence current of the above-mentioned distribution line and the above-mentioned first preset current condition includes the sixth preset current condition, the determination of whether the first monitored current satisfies the first preset current condition to obtain the first determination result includes: determining whether the zero-sequence current satisfies the above-mentioned sixth preset current condition to obtain the above-mentioned first determination result;

[0104] The determination of the protection action strategy for the above-mentioned faulty distribution line according to the above-mentioned first determination result includes: if the first determination result indicates that the zero-sequence current satisfies the above-mentioned sixth preset current condition, then determine the protection action strategy as: controlling the start of the zero-sequence overcurrent acceleration protection for the above-mentioned faulty distribution line.

[0105] Optionally, the above-mentioned configuration of the zero-sequence overcurrent acceleration protection can be switched on and off through the control word. The zero-sequence overcurrent acceleration protection is not blocked by the complex voltage. When the zero-sequence current uses the self-produced zero current, the current transformer CT disconnection alarm blocks the zero-sequence overcurrent acceleration protection. The corresponding sixth preset current condition (i.e., the zero-sequence overcurrent acceleration current condition) can be expressed as:

[0106] I 0 >I set

[0107] In the formula, I 0 is the self-produced or externally connected zero-sequence current corresponding to the faulty distribution line, and I set is the zero-sequence overcurrent acceleration setting value corresponding to the faulty distribution line.

[0108] Optionally, Figure 8 It is a flowchart of an optional zero-sequence overcurrent acceleration protection according to an embodiment of the present invention. As Figure 8 shown, the zero-sequence overcurrent acceleration protection action criterion, in addition to satisfying the above-mentioned sixth preset current condition (i.e., the zero-sequence overcurrent acceleration current condition), also simultaneously satisfies the zero-sequence overcurrent acceleration input: the zero-sequence overcurrent acceleration control word is input; the acceleration condition is satisfied: manual closing or reclosing action; the zero-sequence current is input using the self-produced zero current: in the case where the zero-sequence current uses the self-produced zero current control word to be input, after a preset zero-sequence overcurrent acceleration section time, control the start of the zero-sequence overcurrent acceleration protection for the above-mentioned faulty distribution line.

[0109] In an alternative embodiment, when it is determined that the above line type is a feeder line, the second monitored current corresponding to the faulty distribution line is obtained, where the second monitored current at least includes: the maximum phase current;

[0110] Determine whether the second monitored current satisfies the seventh preset current condition to obtain a second judgment result;

[0111] If the second judgment result indicates that the second monitored current satisfies the seventh preset current condition, determine that the protection action strategy for the faulty distribution line is: control to start the overcurrent protection for the broken phase of the potential transformer for the faulty distribution line.

[0112] As an alternative embodiment, Figure 9 is a flowchart of an alternative overcurrent protection for the broken phase of a potential transformer according to an embodiment of the present invention, as Figure 9 shown, the method includes:

[0113] Optionally, the seventh preset current condition corresponding to the overcurrent protection for the broken phase of the potential transformer can be expressed as:

[0114] I max > Iset

[0115] In the formula, I max为 is the maximum phase current, and I set is the overcurrent setting value for the broken phase of the PT.

[0116] Optionally, still as Figure 9 shown, in addition to satisfying the seventh preset current condition, the faulty distribution line also simultaneously satisfies the input of the overcurrent protection for the broken phase of the current transformer PT: the input of the overcurrent protection for any section via direction or voltage, and the current transformer PT break: the condition of the same bus voltage detection. After a preset overcurrent time for the broken phase of the current transformer PT, control to start the overcurrent protection for the broken phase of the potential transformer for the faulty distribution line.

[0117] Optionally, for the distribution line, an overload alarm function can also be set. As Figure 10 is a flowchart of an alternative overload alarm according to an embodiment of the present invention, as Figure 10 shown, when the distribution line simultaneously satisfies the input of the overload alarm control word and the maximum phase current of the distribution line is greater than the predetermined overload setting value, after reaching the preset overload time, control to start the above overload alarm function.

[0118] In an alternative embodiment, after determining that the protection action strategy is: control to start the differential protection for the faulty distribution line, the method further includes:

[0119] Determine whether the differential protection device corresponding to the faulty distribution line described above operates;

[0120] If the differential protection device corresponding to the faulty distribution line described above does not operate, obtain the differential protection device corresponding to the neighboring distribution line of the faulty distribution line;

[0121] Based on the above protection operation strategy, control the differential protection device corresponding to the neighboring distribution line to operate.

[0122] Optionally, when a fault occurs in a distribution line but the fault cannot be cleared due to a switch failure, obtain the differential protection device corresponding to the neighboring distribution line of the faulty distribution line to expand the differential protection for fault isolation. Figure 11 It is an optional distribution network topology diagram according to an embodiment of the present invention. As Figure 11 shown, when the fault point is at K1, after the differential protection of Line 1 operates, the protection switches DL1 and DL2 are tripped. If the tripping of DL2 fails, an extended differential protection is set between DL1 and DL4 to ensure that when the differential protection of Distribution Line Line1 and Distribution Line Line2 cannot clear the fault, the fault isolation is completed.

[0123] In this embodiment, a protection control device for a distribution line is further provided. This device is used to implement the above embodiments and preferred implementation manners, and those that have been described will not be repeated. As used hereinafter, the terms "module" and "device" may be a combination of software and / or hardware that can achieve a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware is also possible and contemplated.

[0124] According to an embodiment of the present invention, an apparatus embodiment for implementing the above protection control method for a distribution line is further provided. Figure 12 It is a schematic structural diagram of a protection control device for a distribution line according to an embodiment of the present invention. As Figure 12 shown, the above protection control device for a distribution line includes: a first determination module 1200, an acquisition module 1202, a judgment module 1204, and a second determination module 1206, where:

[0125] The above first determination module 1200 is used to determine the faulty distribution line and the line type corresponding to the faulty distribution line;

[0126] The above acquisition module 1202 is used to obtain the first monitored current corresponding to the faulty distribution line when it is determined that the line type is a ring network line;

[0127] The above determination module 1204 is configured to determine whether the above first monitored current satisfies the first preset current condition, and obtain a first determination result;

[0128] The above second determination module 1206 is configured to determine a protection action strategy for the above faulty power distribution line according to the above first determination result.

[0129] It should be noted that the above-mentioned modules can be implemented by software or hardware. For example, for the latter, it can be implemented in the following manner: the above-mentioned modules can be located in the same processor; or, the above-mentioned modules are located in different processors in any combination.

[0130] It should be noted here that the above first determination module 1200, acquisition module 1202, determination module 1204, and second determination module 1206 correspond to steps S102 to S108 in the embodiment. The examples and application scenarios implemented by the above modules and the corresponding steps are the same, but are not limited to the content disclosed in the above embodiment. It should be noted that the above modules, as part of the device, can run in a computer terminal.

[0131] It should be noted that the optional or preferred implementation manners of this embodiment can be referred to the relevant descriptions in the embodiment, and will not be repeated here.

[0132] The above protection control device for a power distribution line may further include a processor and a memory. The above first determination module 1200, acquisition module 1202, determination module 1204, second determination module 1206, etc. are all stored in the memory as program modules, and the processor executes the above program modules stored in the memory to implement corresponding functions.

[0133] The processor contains a kernel, and the kernel retrieves the corresponding program module from the memory. One or more kernels can be set. The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash memory (flash RAM). The memory includes at least one storage chip.

[0134] According to an embodiment of the present application, an embodiment of a non-volatile storage medium is further provided. Optionally, in this embodiment, the above non-volatile storage medium includes a stored program, wherein when the above program runs, it controls the device where the above non-volatile storage medium is located to execute any one of the protection control methods for a power distribution line.

[0135] Optionally, in this embodiment, the non-volatile storage medium may be located in any one of the computer terminals in the computer terminal group in the computer network, or in any one of the mobile terminals in the mobile terminal group. The non-volatile storage medium includes a stored program.

[0136] Optionally, when the program runs, it controls the device where the non-volatile storage medium is located to perform the following functions: determining a faulty power distribution line and the line type corresponding to the faulty power distribution line; when it is determined that the line type is a ring network line, obtaining a first monitored current corresponding to the faulty power distribution line; determining whether the first monitored current meets a first preset current condition to obtain a first judgment result; and determining a protection action strategy for the faulty power distribution line according to the first judgment result.

[0137] According to an embodiment of the present application, an embodiment of a processor is further provided. Optionally, in this embodiment, the processor is used to run a program, where the program, when running, executes any one of the protection control methods for power distribution lines.

[0138] According to an embodiment of the present application, an embodiment of a computer program product is further provided. When executed on a data processing device, it is adapted to execute a program initialized with the steps of any one of the protection control methods for power distribution lines.

[0139] Optionally, when the computer program product is executed on a data processing device, it is adapted to execute a program initialized with the following method steps: determining a faulty power distribution line and the line type corresponding to the faulty power distribution line; when it is determined that the line type is a ring network line, obtaining a first monitored current corresponding to the faulty power distribution line; determining whether the first monitored current meets a first preset current condition to obtain a first judgment result; and determining a protection action strategy for the faulty power distribution line according to the first judgment result.

[0140] An embodiment of the present invention provides an electronic device. The electronic device 10 includes a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, the following steps are implemented: determining a faulty power distribution line and the line type corresponding to the faulty power distribution line; when it is determined that the line type is a ring network line, obtaining a first monitored current corresponding to the faulty power distribution line; determining whether the first monitored current meets a first preset current condition to obtain a first judgment result; and determining a protection action strategy for the faulty power distribution line according to the first judgment result.

[0141] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages and disadvantages of the embodiments.

[0142] In the above embodiments of the present invention, the descriptions of the various embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0143] In the several embodiments provided by the present application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only illustrative. For example, the above-mentioned module division can be a logical function division. In actual implementation, there may be other division methods. For example, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the modules or modules can be in electrical or other forms.

[0144] The modules described above as separate components may or may not be physically separated. The components shown as modules may or may not be physical modules, that is, they can be located in one place or distributed to multiple modules. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0145] In addition, in each embodiment of the present invention, the functional modules can be integrated into a processing module, or each module can exist physically alone, or two or more modules can be integrated into one module. The above-mentioned integrated modules can be implemented in the form of hardware or in the form of software functional modules.

[0146] If the above-mentioned integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can be stored in a computer-readable non-volatile storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a non-volatile storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server or a network device, etc.) to execute all or part of the steps of the methods in the various embodiments of the present invention. And the aforementioned non-volatile storage medium includes: USB flash drives, read-only memories (ROMs), random access memories (RAMs), mobile hard disks, magnetic disks or optical discs and other various media that can store program codes.

[0147] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A protection control method for a distribution line, characterized in that, comprising: determining a faulty distribution line and the line type corresponding to the faulty distribution line; when it is determined that the line type is a ring network line, obtaining a first monitored current corresponding to the faulty distribution line; judging whether the first monitored current meets a first preset current condition to obtain a first judgment result; determining a protection action strategy for the faulty distribution line according to the first judgment result; wherein, when the first monitored current includes the differential current, the differential current change amount, and the zero-sequence differential current of the distribution line, and the first preset current condition includes a second preset current condition, the judging whether the first monitored current meets the first preset current condition to obtain a first judgment result includes: judging whether the differential current, the differential current change amount, and the zero-sequence differential current meet the second preset current condition to obtain the first judgment result; the determining the protection action strategy for the faulty distribution line according to the first judgment result includes: if the first judgment result indicates that at least one of the differential current, the differential current change amount, and the zero-sequence differential current meets the second preset current condition, then determining the protection action strategy as: controlling the initiation of differential protection for the faulty distribution line, wherein, the initiation of differential protection includes at least one of the following: the steady-state quantity differential action element corresponding to the faulty distribution line acts, the change quantity differential action element acts, the zero-sequence current differential action element acts; or when the second preset current condition includes a first sub-preset current condition, the judging whether the first monitored current meets the first preset current condition to obtain a first judgment result includes: judging whether the differential current meets the first sub-preset current condition to obtain the first judgment result; the determining the protection action strategy for the faulty distribution line according to the first judgment result includes: if the first judgment result indicates that the differential current meets the first sub-preset current condition, then determining the protection action strategy as: controlling the steady-state quantity differential action element corresponding to the faulty distribution line to act; or when the above-mentioned second preset current condition includes a second sub-preset current condition, the judging whether the first monitored current meets the first preset current condition to obtain a first judgment result includes: judging whether the differential current change amount meets the second sub-preset current condition to obtain the first judgment result; the determining the protection action strategy for the faulty distribution line according to the first judgment result includes: if the first judgment result indicates that the differential current change amount meets the second sub-preset current condition, then determining the protection action strategy as: controlling the change quantity differential action element corresponding to the faulty distribution line to act; or When the second preset current condition includes a third sub-preset current condition, the judging whether the first monitored current meets the first preset current condition to obtain a first judgment result includes: judging whether the zero-sequence differential current meets the third sub-preset current condition to obtain the first judgment result; and determining a protection action strategy for the faulty distribution line according to the first judgment result includes: if the first judgment result indicates that the zero-sequence differential current meets the third sub-preset current condition, determining the protection action strategy as: controlling the zero-sequence current differential action element corresponding to the faulty distribution line to act. Wherein, the method further includes: when it is determined that the above line type is a feeder line, obtaining a second monitored current corresponding to the faulty distribution line, where the second monitored current at least includes: the maximum phase current; judging whether the second monitored current meets a seventh preset current condition to obtain a second judgment result; if the second judgment result indicates that the second monitored current meets the seventh preset current condition, determining the protection action strategy for the faulty distribution line as: controlling to start overcurrent protection for the voltage transformer broken-phase of the faulty distribution line.

2. The method according to claim 1, characterized in that, when the first monitored current includes the phase current of the distribution line and the first preset current condition includes a third preset current condition, the judging whether the first monitored current meets the first preset current condition to obtain a first judgment result includes: judging whether the phase current meets the third preset current condition to obtain the first judgment result; determining a protection action strategy for the faulty distribution line according to the first judgment result includes: if the first judgment result indicates that the phase current meets the third preset current condition, determining the protection action strategy as: controlling to start negative voltage locked overcurrent protection for the faulty distribution line.

3. The method according to claim 1, characterized in that, when the first monitored current includes the zero-sequence current of the distribution line and the first preset current condition includes a fourth preset current condition, the judging whether the first monitored current meets the first preset current condition to obtain a first judgment result includes: judging whether the zero-sequence current meets the fourth preset current condition to obtain the first judgment result; determining a protection action strategy for the faulty distribution line according to the first judgment result includes: if the first judgment result indicates that the zero-sequence current meets the fourth preset current condition, determining the protection action strategy as: controlling to start zero-sequence overcurrent protection for the faulty distribution line.

4. The method according to claim 1, characterized in that, when the first monitored current includes the maximum phase current of the distribution line and the first preset current condition includes a fifth preset current condition, the judging whether the first monitored current meets the first preset current condition to obtain a first judgment result includes: judging whether the maximum phase current meets the fifth preset current condition to obtain the first judgment result; Determining the protection action strategy for the faulty power distribution line according to the first judgment result includes: If the first judgment result indicates that the maximum phase current meets the fifth preset current condition, determine the protection action strategy as: controlling the start of overcurrent acceleration protection for the faulty power distribution line.

5. The method according to claim 1, wherein, the method further includes: When the first monitored current includes the zero-sequence current of the power distribution line and the first preset current condition includes the sixth preset current condition, the judging whether the first monitored current meets the first preset current condition to obtain a first judgment result includes: judging whether the zero-sequence current meets the sixth preset current condition to obtain the first judgment result; Determining the protection action strategy for the faulty power distribution line according to the first judgment result includes: If the first judgment result indicates that the zero-sequence current meets the sixth preset current condition, determine the protection action strategy as: controlling the start of zero-sequence overcurrent acceleration protection for the faulty power distribution line.

6. The method according to claim 1, wherein, After determining the protection action strategy as: controlling the start of differential protection for the faulty power distribution line, the method further includes: Judging whether the differential protection device corresponding to the faulty power distribution line operates; If the differential protection device corresponding to the faulty power distribution line does not operate, obtain the differential protection device corresponding to the neighboring power distribution line of the faulty power distribution line; Based on the protection action strategy, control the differential protection device corresponding to the neighboring power distribution line to operate.

7. A protection control device for a power distribution line, wherein, it includes: A first determination module for determining a faulty power distribution line and the line type corresponding to the faulty power distribution line; An acquisition module for acquiring the first monitored current corresponding to the faulty power distribution line when determining that the line type is a ring network line; A judgment module for judging whether the first monitored current meets the first preset current condition to obtain a first judgment result; A second determination module for determining the protection action strategy for the faulty power distribution line according to the first judgment result; Wherein, when the first monitored current includes the differential current, differential current change amount, and zero-sequence differential current of the power distribution line and the first preset current condition includes the second preset current condition, the judgment module is further used for: judging whether the differential current, the differential current change amount, and the zero-sequence differential current meet the second preset current condition to obtain the first judgment result; the second determination module is further used for: if the first judgment result indicates that at least one of the differential current, the differential current change amount, and the zero-sequence differential current meets the second preset current condition, determine the protection action strategy as: controlling the start of differential protection for the faulty power distribution line, where the start of differential protection includes at least one of the following: the steady-state quantity differential action element corresponding to the faulty power distribution line operates, the change quantity differential action element operates, the zero-sequence current differential action element operates; or When the second preset current condition includes the first sub-preset current condition, the determination module is further configured to: determine whether the differential current meets the first sub-preset current condition to obtain the first determination result; the second determination module is further configured to: if the first determination result indicates that the differential current meets the first sub-preset current condition, determine the protection action strategy as: controlling the steady-state quantity differential action element corresponding to the faulty distribution line to act; or When the second preset current condition includes the second sub-preset current condition, the determination module is further configured to: determine whether the change amount of the differential current meets the second sub-preset current condition to obtain the first determination result; the second determination module is further configured to: if the first determination result indicates that the change amount of the differential current meets the second sub-preset current condition, determine the protection action strategy as: controlling the change amount differential action element corresponding to the faulty distribution line to act; or When the second preset current condition includes the third sub-preset current condition, the determination module is further configured to: determine whether the zero-sequence differential current meets the third sub-preset current condition to obtain the first determination result; the second determination module is further configured to: if the first determination result indicates that the zero-sequence differential current meets the third sub-preset current condition, determine the protection action strategy as: controlling the zero-sequence current differential action element corresponding to the faulty distribution line to act; Wherein, the device is further configured to: when determining that the line type is a feeder line, obtain a second monitored current corresponding to the faulty distribution line, where the second monitored current at least includes: the maximum phase current; determine whether the second monitored current meets a seventh preset current condition to obtain a second determination result; if the second determination result indicates that the second monitored current meets the seventh preset current condition, determine the protection action strategy for the faulty distribution line as: controlling the start of over-current protection for the voltage transformer disconnection phase of the faulty distribution line.

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