阅读说明：本技术 一种基于5g通信的配网分布式dtu差动保护系统 (Distribution network distributed DTU differential protection system based on 5G communication ) 是由 杜东威 徐东林 强卫 于宙宙 李超 钱彬 姚光 马鹏 严强 梅嵩民 王翔 卢海 于 2020-11-12 设计创作，主要内容包括：本发明公开了一种基于5G通信的配网分布式DTU差动保护系统,包括环网单元,所述环网单元包括基于配网的分布式DTU,所述分布式DTU包括DTU公共单元和DTU间隔单元,所述DTU公共单元集成北斗/GPS功能,对外提供微妙级误差的PPS秒脉冲同步总线,所述DTU间隔单元接入同步总线,不同的所述DTU间隔单元通过过程层交换机、5G CPE接入5G基站,组成端到端通信的5G过程层网络。该系统基于配网分布式DTU产品设计,依靠5G的高可靠低时延通信特性,采用基于北斗/GPS秒脉冲的同步算法,通过IEC61850标准的SV/GOOSE协议实现端到端的数据传输,依靠分相电流纵差保护原理实现基于5G无线网络的快速差动保护功能。(The invention discloses a 5G communication-based distribution network distributed DTU differential protection system, which comprises a ring network unit, wherein the ring network unit comprises a distribution network-based distributed DTU, the distributed DTU comprises a DTU public unit and a DTU interval unit, the DTU public unit integrates the Beidou/GPS function and provides a PPS second pulse synchronization bus with microsecond errors for the outside, the DTU interval unit is accessed into the synchronization bus, and different DTU interval units are accessed into a 5G base station through a process layer switch and a 5G CPE to form a 5G process layer network with end-to-end communication. The system is based on distribution network distributed DTU product design, relies on high-reliability low-time-delay communication characteristics of 5G, adopts a synchronization algorithm based on Beidou/GPS second pulse, realizes end-to-end data transmission through an SV/GOOSE protocol of IEC61850 standard, and relies on a split-phase current longitudinal differential protection principle to realize a rapid differential protection function based on a 5G wireless network.)

1. The utility model provides a join in marriage net distributing type DTU differential protection system based on 5G communication, includes the looped netowrk unit, its characterized in that: the looped netowrk unit includes based on the distributed DTU who joins in marriage the net, the distributed DTU includes DTU common unit and DTU interval unit, the integrated big dipper GPS function of DTU common unit provides the PPS second pulse synchronization bus of microsecond level error externally, DTU interval unit inserts synchronization bus, and is different DTU interval unit passes through process level switch, 5G CPE and inserts 5G basic stations, constitutes the 5G process level network of end-to-end communication.

2. The distribution network distributed DTU differential protection system based on 5G communication of claim 1, wherein the DTU interval units and the DTU interval units adopt an SV/GOOSE protocol of IEC61850 standard to realize end-to-end data transmission. Based on the original sampling value transmitted between the DTU interval units, the DTU interval units calculate the differential current in real time through a synchronous adjustment algorithm.

3. The distribution network distributed DTU differential protection system based on 5G communication of claim 1, wherein the PPS second pulse synchronization bus is based on Beidou/GPS and can realize sampling synchronization of DTU interval units of different ring network units.

4. The distribution network distributed DTU differential protection system based on 5G communication of claim 1, wherein the system takes all DTU interval units in a process layer network as synchronous reference signals based on Beidou/GPS second pulses, a synchronous command is initiated by a host, synchronous sampling is realized based on a ping-pong principle, and the specific flow is as follows:

1) the host computer issues a synchronous command at the arrival time of PPS second pulse, and the message comprises a local side sending time scale (Tm 1);

2) after receiving a synchronization command message sent by the host, the slave extracts a Tm1 time scale, calculates a time difference (td1) between the current time (Tn2) and the previous PPS second pulse generation time (Tn1), performs delay check by combining Tm1, Tn1 and td1, and sends a synchronization response confirmation message to the host after the check synchronization command passes;

4) the master machine receives the synchronous response confirmation message of the slave machine, records the receiving time (Tm2), calculates the time delay (td2), issues a synchronous success command to the slave machine after the time delay check is passed, and starts sampling synchronization at the arrival time of the next PPS second pulse;

5) and the slave receives the synchronization success command of the master, records the time (Tn4), calculates the delay (td3), and starts sampling synchronization at the arrival time of the next PPS second pulse after the delay check is passed.

5. The distribution network distributed DTU differential protection system based on 5G communication as claimed in claim 1, wherein the system adopts split-phase current longitudinal differential protection principle, split-phase current longitudinal differential protection is composed of two elements of differential quick-break protection and ratio differential protection, and the two elements can be independently turned on and off respectively, and is set upIn order to be a differential current flow,for braking current, in the formulaThe current phasor at two ends of the protected line adopts the following equation:

in the first formula: i is_dsetThe threshold is set off for differential flow rate.

The ratio differential criterion is:

in the second formula: i is_dzThe ratio differential threshold is set as a steady-state quantity ratio differential threshold value, the maximum unbalanced current is set when the normal operation is avoided, and the value range is generally (0.3-0.5) I_n(ii) a k is a steady state quantity ratio differential ratio value, which may be fixed at 0.6.

Technical Field

The invention relates to the technical field of wireless differential protection of power distribution networks, in particular to a distribution network distributed DTU differential protection system based on 5G communication, which needs to realize wireless differential protection of a cable line of a power distribution network.

Background

The national planning outline points out that 'the research of the fifth generation mobile communication (5G) and the ultra wide band key technology is actively promoted, and the 5G commercial is started', thereby laying the foundation of the domestic 5G development. The eMBB (enhanced mobile broadband), mMTC (mass machine type communication) and URLLC (high-reliability low-delay communication) application scenarios defined by 5G provide the possibility of differential customization for different industries and different services.

The differential protection has the characteristic of quick action, can realize good protection selectivity, has long-term stable operation experience in a special optical fiber channel environment, but has the defects of multiple points and wide range of distribution networks, multiple circuit topology and great difficulty in economical efficiency and feasibility in the construction of special optical fiber channels. The differential protection based on 4G wireless communication cannot provide reliable support on low time delay and high reliability, but the 5G slice technology provides support for a wireless network environment providing high reliability and low time delay, and provides possibility for realizing the differential protection based on a 5G wireless network. Based on the requirement, the distribution network distributed DTU differential protection system based on 5G communication is invented.

Disclosure of Invention

The invention aims to realize a differential protection function in a 5G wireless network environment, and provides a solution for a power distribution network scene in which the differential protection function needs to be realized and a wired optical fiber environment cannot be built. Based on the design of a distributed DTU product of a distribution network, depending on the high-reliability low-delay communication characteristic of 5G, adopting a synchronization algorithm based on Beidou/GPS second pulse, realizing end-to-end data transmission through an SV/GOOSE protocol of IEC61850 standard, and depending on a split-phase current longitudinal differential protection principle, realizing a rapid differential protection function based on a 5G wireless network.

In order to achieve the purpose, the invention adopts the following technical scheme:

join in marriage net distributing type DTU differential protection system based on 5G communication, including the looped netowrk unit, the looped netowrk unit includes the distributing type DTU based on joining in marriage the net, the distributing type DTU includes DTU common unit and DTU interval unit, the integrated big dipper GPS function of DTU common unit externally provides the synchronous bus of PPS second pulse of microsecond level error, DTU interval unit inserts synchronous bus, and is different DTU interval unit passes through process level switch, 5G CPE and inserts 5G basic station, constitutes the 5G process level network of end-to-end communication.

Furthermore, an SV/GOOSE protocol of IEC61850 standard is adopted between the DTU interval units to realize end-to-end data transmission. Based on the original sampling values transmitted between the DTU interval units, the DTU interval units calculate the differential current in real time through a synchronous adjustment algorithm.

Furthermore, the PPS second pulse synchronization bus is based on the Beidou/GPS, and can realize the sampling synchronization of the DTU interval units of the different ring network units.

Further, the system takes all DTU interval units in a process layer network as synchronous reference signals based on Beidou/GPS second pulses, a synchronous command is initiated by a host, synchronous sampling is realized based on a ping-pong principle, and the specific flow is as follows:

1) the host computer issues a synchronous command at the arrival time of PPS second pulse, and the message comprises a local side sending time scale (Tml);

2) after receiving a synchronization command message sent by the host, the slave extracts a Tm1 time scale, calculates a time difference (td1) between the current time (Tn2) and the previous PPS second pulse generation time (Tn1), performs delay check by combining Tm1, Tn1 and td1, and sends a synchronization response confirmation message to the host after the check synchronization command passes;

4) the master machine receives the synchronous response confirmation message of the slave machine, records the receiving time (Tm2), calculates the time delay (td2), issues a synchronous success command to the slave machine after the time delay check is passed, and starts sampling synchronization at the arrival time of the next PPS second pulse;

5) and the slave receives the synchronization success command of the master, records the time (Tn4), calculates the delay (td3), and starts sampling synchronization at the arrival time of the next PPS second pulse after the delay check is passed.

Besides, the system adopts the split-phase current longitudinal differential protection principle, the split-phase current longitudinal differential protection consists of two elements of differential quick-break protection and ratio differential protection, and the two elements can be independently switched on and off respectively and are arrangedIn order to be a differential current flow,for braking current, in the formulaThe current phasor at two ends of the protected line adopts the following equation:

in the first formula: i is_dsetThe threshold is set off for differential flow rate.

The ratio differential criterion is:

in the second formula: i is_dzSetting a constant value for the ratio differential threshold of the steady-state quantity according to the maximum unbalanced current avoiding normal operation, wherein the value range is generally (0.3-0.5) I_n(ii) a k is a steady state quantity ratio differential ratio value, which may be fixed at 0.6.

The invention has the beneficial effects that:

1. the differential protection solution based on the 5G wireless network is provided, the restrictive requirement that a special optical fiber channel must be laid in the traditional differential protection is changed, and the investment and construction cost is greatly saved.

2. The differential protection method provides another novel solution for the power distribution network with the need of realizing the differential protection function, can realize the rapid selective protection of line faults by means of the differential protection, and solves the problem that the prior distribution network line needs to realize the selectivity by means of the level difference coordination.

3. An effective solution is provided for the application of 5G communication in a power distribution network, and a product design concept and an application scheme which can be applied to 5G differential protection are provided for the industry.

Drawings

Fig. 1 is a schematic diagram of a distribution network distributed DTU differential protection system based on 5G communication according to the present invention.

Fig. 2 is a schematic diagram of a 5G differential protection sampling synchronization algorithm of a distribution network distributed DTU differential protection system based on 5G communication according to the present invention.

Fig. 3 is a schematic diagram of a 5G split-phase current longitudinal differential protection principle of a distribution network distributed DTU differential protection system based on 5G communication according to the present invention.

Detailed Description

The technical solution of the present patent will be described in further detail with reference to the following embodiments.

As shown in fig. 1, the 5G differential protection of the distribution network ring network line is realized based on the distributed DTU, and the whole system is composed of three major parts, namely a synchronous bus, a process layer network and a 5G end-to-end network. The DTU public unit is connected to a Beidou/GPS network and provides microsecond PPS synchronous pulse signal output, the DTU interval unit acquires synchronous signals from a synchronous bus to realize sampling adjustment and synchronization of each interval unit, and the DTU interval units among different ring network units realize microsecond sampling synchronization. The process layer network inside the ring network unit is realized by a 5G CPE cascading process layer switch, and the DTU interval unit is connected into the process layer switch. The 5G network is accessed to a 5G core network through 5G CPE among different ring network units, and 5G communication among the ring network units is realized.

The DTU interval unit supports an SV and GOOSE protocol based on IEC61850, information interaction of sampling values and switching values between the looped network units is realized through a process layer network and a 5G network, and a wireless differential protection function of a cable line is realized based on split-phase current longitudinal difference.

The wireless differential protection based on 5G communication is realized, and the synchronization technology among devices is key. Only if the sampling synchronization of the whole-line device is realized, the correct data synchronization adjustment can be realized under different wireless network delay working conditions, and the accuracy of the subsequent protection algorithm can be ensured.

As shown in fig. 2, in the scheme, all DTU interval units in a process layer network are used as synchronous reference signals based on Beidou/GPS second pulse, a synchronous command is initiated by a host, synchronous sampling is realized based on a ping-pong principle, and the specific flow is as follows:

1) the host computer issues a synchronous command at the arrival time of PPS second pulse, and the message comprises a local side sending time scale (Tm 1);

2) after receiving a synchronization command message sent by the host, the slave extracts a Tm1 time scale, calculates a time difference (td1) between the current time (Tn2) and the previous PPS second pulse generation time (Tn1), performs delay check by combining Tm1, Tn1 and td1, and sends a synchronization response confirmation message to the host after the check synchronization command passes;

4) the master machine receives the synchronous response confirmation message of the slave machine, records the receiving time (Tm2), calculates the time delay (td2), issues a synchronous success command to the slave machine after the time delay check is passed, and starts sampling synchronization at the arrival time of the next PPS second pulse;

5) and the slave receives the synchronization success command of the master, records the time (Tn4), calculates the delay (td3), and starts sampling synchronization at the arrival time of the next PPS second pulse after the delay check is passed.

Regarding the delay check in the above process, it means that any party must be within one pulse-per-second interval from the last PPS pulse received from the packet, if it exceeds one pulse-per-second interval, the checking party is responsible for sending synchronization failure information to another party, at this time, synchronization fails, and locks the relevant protection logic, and requests synchronization again in the next synchronization period. Under the slicing technology support of 5G high-reliability low-delay communication (URLLC), a time window of 1 second is sufficient to support the completion of sampling synchronization between devices.

The split-phase current longitudinal differential protection is based on the transmission of original sampling values between devices, and the devices calculate differential flow in real time through a synchronous adjustment algorithm. According to the scheme, end-to-end sampling value transmission is realized based on an SV protocol of IEC61850 standard. The split-phase current longitudinal differential protection consists of two elements of differential quick-break protection and ratio differential protection, and the two elements can be independently switched on and off respectively.

As shown in fig. 3, the coordinates in the figureIn order to be a differential current flow,for braking current, in the formulaThe current phasor at two ends of the protected line (the positive directions of the currents at two sides are both regulated to flow from the bus to the line). The shadow region is a protection action region, wherein_dsetThe above is the differential quick-break protection operation area, the other partDivided into ratio differential protection action zones.

In the first formula: i is_dsetThe threshold is set off for differential flow rate.

The ratio differential criterion is:

in the second formula: i is_dzSetting a constant value for the ratio differential threshold of the steady-state quantity according to the maximum unbalanced current avoiding normal operation, wherein the value range is generally (0.3-0.5) I_n(ii) a k is a steady state quantity ratio differential ratio value, which may be fixed at 0.6.