GB2625495A

GB2625495A - Method and apparatus for discriminating consistency of receiving and sending delays of differential channel, and electronic device and differential protection

Info

Publication number: GB2625495A
Application number: GB2405340.7A
Authority: GB
Inventors: Zhang Hongxi; Zhao Qinchun; Xu Xiaochun; Xu Haiyang; Xie Hua; Dai Guangwu; Lu Jinfeng; Bu Lizhi; Li Ben
Original assignee: NR Electric Co Ltd; NR Engineering Co Ltd
Current assignee: NR Electric Co Ltd; NR Engineering Co Ltd
Priority date: 2021-11-18
Filing date: 2022-09-29
Publication date: 2024-06-19
Also published as: GB202405340D0; CN114050559A; WO2023087943A1

Abstract

Disclosed in the present application are a method and apparatus for discriminating the consistency of receiving and sending delays of a differential channel, and an electronic device and a differential protection communication system, which are used for a host side or a slave side of a differential channel. The method comprises: calculating a channel delay of a differential channel; adjusting sampling data on two sides of the differential channel to a synchronous state; calculating, in real time, a variation amount of the channel delay, and when the variation amount of the channel delay is greater than a first threshold value, starting to discriminate the consistency of receiving and sending delays of the differential channel, so as to obtain a discrimination result of the consistency of the receiving and sending delays of the channel; and according to the discrimination result of the consistency of the receiving and sending delays of the channel, determining whether to lock differential protection.

Description

METHOD AND APPARATUS FOR DISCRIMINATING CONSISTENCY

OF RECEIVING AND SENDING DELAYS OF DIFFERENTIAL

CHANNEL, AND ELECTRONIC DEVICE AND DIFFERENTIAL

PROTECTION COMMUNICATION SYSTEM

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Chinese Patent Application No. 2021113736564, filed with the China National Intellectual Property Administration on November 18, 2021 and entitled "DETERMINATION METHOD AND APPARATUS FOR CONSISTENCY OF SENDING AND RECEIVING DELAYS OF DIFFERENTIAL CHANNEL, AND DIFFERENTIAL PROTECTION COMMUNICATION SYS LEM", which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

This application relates to the field of electrical engineering technologies, and in particular, to a determination method and apparatus for consistency of sending and receiving delays of a differential channel, an electronic device, and a differential protection communication system.

BACKGROUND

With the development of communication technologies, differential protection has been widely applied. In the field of differential protection technologies, longitudinal differential protection has the advantages such as a clear protection range, a simple principle, stability, and reliability. In differential protection, information is exchanged using a communication network, information, such as a current amount, on a remote side is transmitted to a local side, a differential current and a restrained current are calculated according to currents on the local side and the remote side, and it is determined whether there is an internal fault based on differential action characteristics.

A premise of normal operation of the differential protection is data synchronization between the local side and the remote side. Therefore, the two-side data synchronization technology is a key to implementing differential protection. Existing common line differential protection synchronization methods include a synchronous clock source method, a Ping-Pong method, a reference phasor method, and the like. The Ping-Pong method is widely applied to differential protection because it does not rely on an external timing source and is stable and reliable

SUMMARY

Exemplary embodiments of this application aim to provide a determination method and apparatus for inconsistency of sending and receiving delays of a differential channel and a differential protection communication system, to overcome, through real-time determination on consistency of sending and receiving delays of a channel, the defect that consistency of a differential channel cannot be monitored and find inconsistency of sending and receiving delays of a channel in time. Through the method, a single-channel mode and a double-channel mode can be determined, and when sending and receiving delays of a channel are inconsistent, differential protection is blocked in time, to improve the reliability and stability of a differential protection function. In addition, this method does not rely on an external timing source, does not increase additional costs, and does not consume additional resources.

According to an embodiment of this application, a determination method for consistency of sending and receiving delays of a differential channel is provided, applicable to a master side or a slave side of the differential channel, the method including.

calculating a channel del ay of the differential channel; adjusting sampling data on both sides of the differential channel to a synchronized state; calculating a variation of the channel delay in real time, and activating determination on consistency of sending and receiving delays of the channel when the variation of the channel delay is greater than a first threshold, to obtain a determination result of the consistency of the sending and receiving delays of the channel; and determining, according to the determination result of the consistency of the sending and receiving delays of the channel, whether to block differential protection.

In an optional embodiment, when the variation of the channel delay is greater than the first threshold, a first differential protection pickup threshold is changed to a second differential protection pickup threshold, where the second differential protection pickup threshold is greater than the first differential protection pickup threshold.

In an optional embodiment, when the determination result of the consistency of the sending and receiving delays of the channel is that the sending and receiving delays of the channel are consistent, after delay confirmation, the second differential protection pickup threshold is changed back to the first differential protection pickup threshold; and when the determination result of the consistency of the sending and receiving delays of the channel is that the sending and receiving delays of the channel are inconsistent, the differential protection is blocked.

In an optional embodiment, the step of adjusting sampling data on both sides of the differential channel to a synchronized state includes: calculating an error At between a sampling moment on the master side and a sampling moment on the slave side according to the channel delay after the channel delay is calculated; and maintaining the sampling moment on the master side unchanged, and adjusting the sampling moment on the slave side gradually until At approaches 0.

In an optional embodiment, the step of calculating a variation of the channel delay in real time, and activating determination on consistency of sending and receiving delays of the channel when the variation of the channel delay is greater than a first threshold includes: calculating a channel delay value Td(K) of a current sampling point K in real time, and comparing the channel delay value Td(K) with a channel delay value Td(K-1) of a previous sampling point K-1, to obtain a variation AL of the channel delay, where a calculation formula of the variation ATd is as follows: ATd=abs(Td(K)-Td(K-1)), where abs represents finding an absolute value, and the determination on the consistency of the sending and receiving delays of the channel is activated when the variation ATd of the channel delay is greater than the first threshold.

In an optional embodiment, the step of activating determination on consistency of sending and receiving delays of the channel includes: activating, in a case that a single channel is used, a determination method for consistency of sending and receiving delays of the channel in a single-channel mode; or activating, in a case that double channels are used, a determination method for consistency of sending and receiving delays of the channels in a double-channel mode.

In an optional embodiment, the activating a determination method for consistency of sending and receiving delays of the channel in a single-channel mode includes: determining, in a case that neither of protection apparatuses on the both sides of the differential channel picks up, and in addition, both three-phase differential currents 'Dim, are greater than a first threshold set value both three-phase differential current variations Al",", are greater than a second threshold set value AID,,"" and both three-phase restrained current variations Aim,* are less than a third threshold set value AIR,"t, that the sending and receiving delays of the channel are inconsistent, where a calculation formula for the three-phase differential current variation and the three-phase restrained current variation is as follows: fAct= lInt-(k)-1f,d)0(k - h (k) and tBias,"(k) are respectively a three-phase differential current and a three-phase restrained current of the current sampling point; and %dig, (k -n) and I Ems,,(k -10 are respectively a three-phase differential current and a three-phase restrained current one cycle before, where n is a quantity of sampling points of one cycle.

In an optional embodiment, the activating a determination method for consistency of sending and receiving delays of the channels in a double-channel mode includes: selecting, when a variation AL of a channel delay of only one of the double channels is greater than the first threshold, a channel whose variation AL of a channel delay is less than or equal to the first threshold as a first channel and the other channel as a second channel, and adjusting sampling data on both sides of the double channels to the synchronized state with the channel delay of the first channel as a reference; and calculating the channel delay of the second channel, where the slave side calculates the error At between the sampling moment on the slave side and the sampling moment on the master side according to the channel delay of the second channel, where when the error At is less than the second threshold, it is determined that the sending and receiving delays of the second channel are consistent; and when the error At is greater than or equal to the second threshold, it is determined that the sending and receiving delays of the second channel are inconsistent.

In an optional embodiment, the activating a determination method for consistency of sending and receiving delays of the channels in a double-channel mode includes: selecting, when both variations AL of channel delays of two channels in the double channels are greater than the first threshold, a channel whose variation of a channel delay is smaller as a first channel and a channel whose variation of a channel delay is larger as a second channel; and and adjusting sampling data on both sides of the first channel to the synchronized state, and then, performing determination on consistency of the sending and receiving delays of the channel on the first channel according to the determination method for consistency of sending and receiving delays of the channel in a single-channel mode. w ere

In an optional embodiment, the channel delay of the second channel is calculated when a determination result of the first channel is that the sending and receiving delays of the first channel are consistent, where the slave side calculates the error At between the sampling moment on the slave side and the sampling moment on the master side according to the channel delay of the second channel, where when the error At is less than the second threshold, it is determined that the sending and receiving delays of the second channel are consistent; and when the error At is greater than or equal to the second threshold, it is determined that the sending and receiving delays of the second channel are inconsistent.

In an optional embodiment, when it is determined that the sending and receiving delays of the first channel are inconsistent, sampling data on both sides of the double channels is adjusted to the synchronized state with the channel delay of the second channel as a reference, and then, the second channel is determined according to the determination method for consistency of sending and receiving delays of the channel in a single-channel mode.

In an optional embodiment, the step of calculating a channel delay of the differential channel includes: sending, by the slave side, a first frame of message to the master side, and recording a sending moment tss; when receiving the first frame of message, recording, by the master si_dnes: a receiving moment t",,-, returning a second frame of message to the slave side at a moment t and at the same time, sending a time difference (mns--mr,t t 1 as message content of the second frame of message to the slave side; and receiving, by the slave side, the returned second frame of message at a moment td-, and extracting the time difference (tms-t.,-) from the second frame of message, where the channel delay Td is obtained through the following formula: (t -t) -(t -t) In an optional embodiment, after the step of adjusting sampling data on both sides of the differential channel to a synchronized state, the method further includes: calculating a differential current and a restrained current through the following formula according to synchronized current data on the both sides: { !Emit -lit and ICE,* are respectively currents on the master side and the slave side in a 0 phase, and and Imas* are respectively the differential current and the restrained current in the where H tYitE", (I) phase.

According to another embodiment of this application, a determination apparatus for consistency of sending and receiving delays of a differential channel is provided, including: a delay calculation module, configured to calculate a channel delay of the differential channel; a synchronization module, configured to adjust sampling data on both sides of the differential channel to a synchronized state; a delay variation monitoring module, configured to calculate a variation of the channel delay in real time, and activate determination on consistency of sending and receiving delays of the channel when the variation of the channel delay is greater than a first threshold and a determination module, configured to perform determination on the consistency of the sending and receiving delays of the channel.

According to an aspect of this application, an electronic device is provided, including: a memory, a processor, and a computer program stored in the memory and executable by the processor, where the processor implements the steps of the method according to any one of the foregoing aspects when executing the computer program.

According to another aspect of this application, a differential protection communication system is provided, including the apparatus as stated above and/or the electronic device as stated above.

In the related art, the premise of the Ping Pong method requires that sending and receiving delays of a channel are consistent. To improve the reliability of data transmission of differential protection, the communication network generally has a self-healing function. In other words, when the communication device fails, channel routes can be automatically switched within a short period of time. In this case, delays of sending and receiving routes may be inconsistent. If sending and receiving delays of a channel are inconsistent, the premise of the Ping Pong method is destroyed, resulting in false synchronization, which affects reliability of differential protection and may cause a differential malfunction in an extreme case.

When sending and receiving delays of a channel are inconsistent, theoretically, synchronization between data on both sides can be achieved through external timing. However, due to conditional restrictions, some countries and regions do not have external timing conditions. In addition, external timing is greatly affected by the environment, and its stability cannot be guaranteed According to an exemplary embodiment of this application, this application provides a determination method for inconsistency of delays of a differential channel, to resolve the problem that consistency of delays of a differential channel cannot be monitored without external timing Consistency of sending and receiving delays of a channel can be determined, and it is selected, according to a determination result, whether to block differential protection, which improves the reliability and stability of differential protection.

It should be understood that the foregoing general descriptions and the following detailed descriptions are merely illustrative, and are not intended to limit this application.

BRIEF DESCRIPTION OF THE DRAWINGS

To describe the technical solutions in the embodiments of this application more clearly, the following briefly describes the accompanying drawings required for describing the embodiments.

FIG. 1 illustrates a schematic diagram of a differential protection communication system according to an exemplary embodiment of this application; FIG. 2A and FIG. 2B illustrate schematic diagrams of channel delay calculation and sampling moment adjustment based on a Ping Pong method according to an exemplary embodiment of this application; FIG. 3 illustrates a flowchart of a determination method for consistency of sending and receiving delays of a differential channel according to an exemplary embodiment of this application; FIG. 4 illustrates a logic diagram of determination on consistency of sending and receiving delays in a single-channel mode according to an exemplary embodiment of this application; FIG. 5A and FIG. 5B illustrate schematic diagrams of sampling synchronization between a channel A and a channel B in a double-channel mode according to an exemplary embodiment of this application; FIG. 6 illustrates a block diagram of a determination apparatus for inconsistency of sending and receiving delays of a differential channel; and FIG. 7 illustrates a block diagram of an electronic device according to an exemplary embodiment.

DETAILED DESCRIPTION

At present, the exemplary embodiments are described comprehensively with reference to the accompanying drawings. However, the exemplary embodiments can be implemented in a plurality of forms, and it should not be understood as being limited to the embodiments described herein. Conversely, the embodiments are provided to make this application more comprehensive and complete, and comprehensively convey the idea of the exemplary embodiments to a person skilled in the art. A same reference numeral in the accompanying drawings represents same or similar components, and therefore repeated descriptions of the components are appropriately omitted.

In addition, the described features, structures, or characteristics may be combined in one or more embodiments in any appropriate manner. In the following descriptions, a lot of specific details are provided to give a full understanding of the embodiments of this application. However, a person skilled in the art is to be aware of that, the technical solutions in this application may be implemented without one or more of the particular details, or other methods, unit, apparatus, or step may be adopted. In other cases, well-known methods, apparatuses, implementations, or operations are not shown or described in detail, to avoid obscuring the aspects of this application.

Unless otherwise specified in the context, the block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. In other words, such functional entities may be implemented in the form of software, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and/or processor apparatuses and/or microcontroller apparatuses.

The flowcharts shown in the accompanying drawings are merely examples for descriptions, do not necessarily include all content and operations/steps, and are not necessarily performed in the described orders. For example, some operations/steps may be further divided, while some operations/steps may be combined or partially combined. Therefore, an actual execution order may vary depending on an actual situation.

It should be understood that the terms such as "first", "second", and "third" used in this specification may be used for describing various components. However, the components are not limited by the terms. The terms are used for distinguishing a component from another component. Therefore, the first component discussed in the following may be referred to as a second component without departing from the teaching of the concept of this application. As used in this specification, the term "and/or" used includes any or all combinations of one or more related listed items.

A person skilled in the art may understand that, the accompanying drawings are merely schematic diagrams of exemplary embodiments, and modules or processes are not necessarily required for implementing this application, and therefore cannot be used for limiting the protection scope of this application.

In the related art, data exchanges between apparatuses on both sides of a differential protection channel usually adopt a multiplexing manner, that is, are implemented through external communication networks. These networks are usually self-healing ring networks. When an original transmission channel fails, data exchanges are automatically switched to a backup channel within a short period of time. It is likely that the switched channel may have inconsistent delays in sending and receiving routes, that is, the premise of differential synchronization (requiring that delays in sending and receiving routes are consistent) is destroyed. Once the delays in the sending and receiving routes are inconsistent, and the apparatuses do not determine the inconsistency, the apparatuses are in a risk of malfunction.

To resolve the foregoing problems and improve the stability of differential protection, exemplary embodiments of this application provide a determination method for consistency of sending and receiving delays of a differential channel, which may also be understood as a determination method for inconsistency of sending and receiving delays of a differential channel. In this method, on the premise that sending and receiving delays of a channel are consistent, based on the Ping Pons method, a channel delay is calculated, differential data on both sides is adjusted to a synchronized state, and a variation of the channel delay is calculated in real time. When the variation of the channel delay is greater than a set value, a differential protection pickup threshold is raised immediately, and at the same time, determination on consistency of sending and receiving delays of a differential channel is activated. The determination on consistency of sending and receiving delays may include determination on consistency of sending and receiving delays in a single-channel mode and determination on consistency of sending and receiving delays in a double-channel mode. When it is determined that sending and receiving delays of a channel are consistent, after delay confirmation, an original differential protection function is restored. When it is determined that the sending and receiving delays are inconsistent, an alarm signal is output, and a differential protection function is blocked immediately. The differential protection function is enabled again after the channel is restored.

The determination method for consistency of delays of a differential channel provided in the exemplary embodiments of this application resolves the problem that consistency of delays of a differential channel cannot be monitored without external timing. In this method, consistency of sending and receiving delays of a channel can be determined, and it is selected, according to a determination result, whether to block differential protection, which improves the reliability and stability of differential protection.

The technical solutions of this application are described below in detail with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a differential protection communication system according to an exemplary embodiment of this application.

In the differential protection communication system shown in FIG. I, a communication channel (for example, a communication network) whose two ends are connected to differential protection apparatuses is a differential protection channel, that is, a differential channel, configured for data exchanges between the differential protection apparatuses on both sides of the differential channel. One end of the differential channel is connected to a master machine, and the other end thereof is connected to a slave machine, to perform delay calculation and synchronization adjustment on the channel.

FIG. 3 is a flowchart of a determination method for consistency of sending and receiving delays of a differential channel according to an exemplary embodiment of this application.

According to an exemplary embodiment, a channel delay is calculated based on the Ping Pong method, and sampling data on both sides is adjusted to a synchronized state.

Referring to FIG. 3, in step S301, a channel delay of a differential channel is calculated.

With reference to the exemplary embodiment shown in FIG. 2A, an M side is selected as a master side, and an N side is selected as a slave side. The slave side sends a frame of message to the master side, and records a sending moment tss. When receiving the frame of message, the master side records a receiving moment t returns a frame of message to the slave side at a moment t., and at the same time, transmits a time difference (tms-tmr) as message content to the slave side. The slave side receives the returned message at a moment kr, and extracts the t.) information from the message, to calculate a channel delay Td, as shown in a formula (t -t)-(t -t) T, - " ' (1) In step S303, sampling data on both sides of the differential channel is adjusted to a synchronized state.

With reference to the exemplary embodiment shown in FIG. 2B, after the channel delay Td is calculated, the slave side calculates an error At between a sampling moment on the slave side and a sampling moment on the master side according to the channel delay. Subsequently, the sampling moment on the master side is maintained unchanged, the slave side gradually adjusts the sampling moment thereon until At approaches 0, to achieve synchronization between the sampling data on the both sides.

A differential current and a restrained current are calculated according to synchronized current data on the both sides, as shown in a formula (2)-IDiffT 14?-fle, +(CVO), where + lit & and ez-are respectively currents on the M side and the N side in a (I) phase, and MC) Nct, I 'VIM and kist are respectively the differential current and the restrained current in the (I) phase.

In step S305, a variation of the channel delay is calculated in real time, and determination on consistency of sending and receiving delays of the channel is activated when the variation of the channel delay is greater than a first threshold.

When the variation of the channel delay is greater than the first threshold, a differential protection pickup threshold is raised, and at the same time, determination on consistency of sending and receiving delays of the channel is activated. That is, a first differential protection pickup threshold is changed to a second differential protection pickup threshold, where the second differential protection pickup threshold is greater than the first differential protection pickup threshold.

During real-time calculation of the channel delay, a method for activating determination on the consistency of the sending and receiving delays of the channel may include: calculating a channel delay value Td(K) of a current sampling point K in real time, and comparing the channel delay value Td(K) with a channel delay value Td(K-1) of a previous sampling point, to obtain a delay variation ATd, as shown in formula 3: ATd=abs(Td(K)-Td(K-1)) (3) abs represents finding an absolute value, and the determination on the consistency of the sending and receiving delays of the channel is activated when the variation ATd of the channel delay is greater than the first threshold.

When the delay variation AL is greater than a threshold set value Tsci., the determination on the consistency of the sending and receiving delays of the channel is activated.

The differential protection apparatus provides two independent differential protection functions, each of which can be enabled or disabled independently. When a specific protection function is enabled, there is a corresponding enabled mark. It is determined based on enabled marks of the two protection apparatuses whether the channel is enabled. One apparatus provides two independent differential protection functions. A user determines, according to a status of an external channel, to use a single channel or double channels, which requires that each differential protection function can be independently enabled or disabled. For example, in an application to a single-channel scenario, only one differential protection function needs to be enabled for cooperation with the single-channel scenario, and the other one needs to be disabled. For example, in an application to a double-channel scenario, both differential protection functions need to be enabled.

Consistency of sending and receiving delays of a channel is automatically identified according to an enabled status of the channel. The enabled status of the channel includes that a single channel is enabled and that double channels are enabled. When a single channel is enabled, determination on consistency of sending and receiving delays of the channel in a single-channel mode is adopted. When double channels are enabled, determination on consistency of sending and receiving delays of the channels in a double-channel mode is adopted.

Using the single-channel mode as an example, a determination method for consistency of sending and receiving delays of the channel in a single-channel mode is described below.

The determination method for consistency of sending and receiving delays of the channel in a single-channel mode may include the following step: During activation of determination on consistency of sending and receiving delays of a single channel, neither of apparatuses on both sides picks up. The protection apparatus diagnoses in real time whether the system is faulty. When detecting that the system is faulty, the protection apparatus picks up and sends a pickup signal.

FIG. 4 is a logic diagram of determination on inconsistency of sending and receiving delays in a single-channel mode according to an exemplary embodiment of this application.

Referring to FIG. 4, in a case that the calculated channel delay variation ATd is greater than the set threshold Let, neither of the apparatuses on the both sides picks up, and in addition, both three-phase differential currents Int"," are greater than a first threshold set value Ir,tfflot, both three-phase differential current variations 41,,,, are greater than a second threshold set value Al",,"" and both three-phase restrained current variations Alwate, are less than a third threshold set value 41,,,st, , it is determined that the sending and receiving delays of the channel are inconsistent A calculation formula for the three-phase differential current variation and the three-phase restrained current variation is as follows: AI =11""a, (k)-(k -n)1 Aladsc. = 11,", (k)-I (4), where E,,(k -n)1 (k) and (k) are respectively a three-phase differential current and a three-phase restrained current of the current sampling point; and In addition, (k -n) and (k -n) are respectively a three-phase differential current and a three-phase restrained current one cycle before.

In the single-channel mode, when the channel delay variation ATd calculated in real time is greater than the threshold set value -Let, determination on consistency of sending and receiving delays of the channel is activated. The consistency of the sending and receiving delays of the channel is determined according to the three-phase differential current, the three-phase differential current variation, and the three-phase restrained current variation, where determination conditions are: the three-phase differential current 1Djft > , the three-phase differential current variation Alf,, ,",> AID11.1, and the three-phase restrained current variation AI,,w < AIthassot, where (I) represents any one of three phases, and during determination, the foregoing conditions need to be met in all the three phases.

Using the double-channel mode as an example, a determination method for consistency of sending and receiving delays of the channels in a double-channel mode is described below.

The determination method for consistency of sending and receiving delays of the channels in a double-channel mode includes: determination on consistency when a delay of one channel changes and determination on consistency when delays of two channels simultaneously change in the double-channel mode.

1) First case In the double-channel mode, a determination method for consistency when a delay of one channel changes may be: When a delay of a channel A does not change, and a delay of a channel B changes, synchronization adjustment is performed by selecting the channel A as a reference.

In the double-channel mode, a channel delay TdA is calculated according to the formula (1) using the channel A as a reference. Then, sampling moments on both sides are calculated according to LA, and a sampling moment on a slave side (N side) is adjusted until the sampling moments are completely synchronized. Synchronized sampling moments of the channel A are shown in FIG. SA.

Subsequently, likewise, a channel delay TdB of the channel B is calculated according to the formula (1). Then, a theoretical sampling moment on a slave side (N side) is calculated according to the channel delay TdB. The theoretical sampling moment is compared with an actual sampling moment (the actual sampling moment has been adjusted and synchronized through the channel A), to calculate a sampling moment difference AtB. Then, it is determined according to a value of AtB whether sending and receiving delays of the channel B are consistent. When the sending and receiving delays of the channel B are inconsistent, a sampling moment error is shown in FIG. 5B.

In an optional embodiment, the foregoing determination method may include the following steps. First, a delay TdA of a channel A is calculated, and synchronization adjustment is performed with TdA as a reference. Sampling moments on both sides after the adjustment are consistent. LA is a specific sampling moment after the sampling synchronization adjustment on the channel A. Then, a delay TdB of a channel B is calculated, where the delay TdB of the channel B is deduced according to a data receiving moment LB of the channel B, so that a theoretical sampling moment LB of the channel B on a local side is obtained, and further, a sampling moment difference between the two channels is obtained as AtB=abs(LA-LB).

When sending and receiving delays of the channel B are consistent, AtB is a value equal to 0 (which should be, in consideration of an error, a value approaching 0). When the sending and receiving delays of the channel B are inconsistent, AtB is a value greater than 0. Therefore, it is determined, according to the value of AtB, whether the delays of the channel B are consistent. In an embodiment, when MB is greater than or equal to a set threshold it may be determined that the sending and receiving delays are inconsistent.

2) Second case In the double-channel mode, a determination method for consistency when delays of two channels simultaneously change may be: When the delays of the two channels change, the one with a smaller delay variation (set as a channel A) is used as a reference for synchronization adjustment, and at the same time, determination for consistency of delays of a channel is perfomned on the channel A according to the foregoing determination method for consistency of sending and receiving delays of the channel in a single-channel mode.

If delays of the channel A are consistent, determination for consistency of delays of a channel is performed on the other channel (channel B). The determination method is the same as the method in the first case in 1).

If it is determined that sending and receiving delays of the channel A are inconsistent, synchronization adjustment is then performed using the channel B as a reference. Then, determination for consistency of delays of a channel is performed on the channel B according to the foregoing determination method for consistency of sending and receiving delays of the channel in a single-channel mode.

Specifically, a delay Td of the channel B is calculated. A slave side calculates an error At between a sampling moment on the slave side and a sampling moment on a master side according to the delay Ti of the channel B. Subsequently, the sampling moment on the master side is maintained unchanged, the slave side gradually adjusts the sampling moment thereon until At approaches 0, to achieve synchronization between sampling data on the both sides.

A differential current and a restrained current are calculated through the formula (2) according to synchronized current data on the both sides.

Then, a three-phase differential current, a three-phase differential current variation, and a three-phase restrained current variation are calculated according to a formula (4), to determine whether the following conditions are all met: the three-phase differential current Lop the three-phase differential current variation Alr,ilm,> Alraffi" , and the three-phase restrained current variation In step S307, it is determined, according to the determination result of the consistency of the sending and receiving delays of the channel, whether to block differential protection.

When it is determined that the delays of the channel are inconsistent, an alarm signal is output, and the differential protection is blocked. After the determination for the consistency of the delays of the channel, if the determination result is that the delays of the channel are inconsistent, an alarm signal indicating that the sending and receiving delays of the corresponding channel are inconsistent is output, and at the same time, a differential protection function of the channel is blocked, and differential protection is enabled again after the channel is restored.

It should be clearly understood that, this application describes how to form and use specific examples, but this application is not limited to any detail of the examples. Conversely, based on the teaching of the disclosure of this application, the principles can be applied to many other embodiments.

A person skilled in the art may understand that all or some of the steps of the foregoing embodiments are implemented as computer programs executed by a CPU. When the computer programs are executed by the CPU, programs implementing the foregoing functions defined in the foregoing method provided in this application may be stored in a computer-readable storage medium. The storage medium may be a read-only memory, a magnetic disk, an optical disc, or the like In addition, the foregoing accompanying drawings are merely schematic descriptions of processing included in the methods of exemplary embodiments in this application, and are not used for a limitative purpose. It is easily understood that the processes illustrated in the foregoing accompanying drawings do not indicate or define the chronological order of these processes. In addition, it is also easily understood that these processes may be performed, for example, synchronously or asynchronously in a plurality of modules.

Through the description of the exemplary embodiments, a person skilled in the art may easily understand that the determination method for inconsistency of sending and receiving delays of a differential channel according to the embodiments of this application has at least one or more of the following advantages.

According to the exemplary embodiments, through real-time determination on consistency of sending and receiving delays of a channel, the defect that consistency of a differential channel cannot be monitored is overcome, and inconsistency of sending and receiving delays of a channel is found in time.

According to an exemplary embodiment, the method may be used to perform determination in a single-channel mode and a double-channel mode. When delays of a channel are inconsistent, differential protection is blocked in time.

According to exemplary embodiment, this method improves reliability and stability of a differential protection function In addition, this method does not rely on an external timing source, does not increase additional costs, and does not consume additional resources.

An apparatus embodiment of this application is described below, and may be used to perform the method embodiments of this application. For details not disclosed in the apparatus embodiment of this application, reference may be made to the foregoing method embodiments in this application, FIG 6 is a block diagram of a determination apparatus for inconsistency of sending and receiving delays of a differential channel.

The apparatus shown in FIG. 6 may perform the steps of the determination method for consistency of sending and receiving delays of a differential channel according to the embodiments of this application As shown in FIG. 6, the determination apparatus for inconsistency of sending and receiving delays of a differential channel may include a delay calculation module 610, a synchronization module 620, a delay variation monitoring module 630, and a determination module 640.

Referring to FIG. 6 and the foregoing descriptions, the delay calculation module 610 is configured to calculate a channel delay.

The synchronization module 620 is configured to adjust sampling data on both sides of the differential channel to a synchronized state.

The delay variation monitoring module 630 is configured to calculate a variation of the channel delay in real time, and activate determination on consistency of sending and receiving delays of the channel when the variation of the channel delay is greater than a first threshold.

The determination module 640 configured to perform determination on the consistency of the sending and receiving delays of the channel.

The apparatus implements the functions similar to those of the methods provided above. For other functions, reference may be made to the foregoing descriptions, and details are not described herein again.

FIG. 7 is a block diagram of an electronic device according to an exemplary embodiment.

An electronic device 200 according to this implementation of this application is described below with reference to FIG. 7. The electronic device 200 shown in FIG. 7 is only an example, and does not impose any limitation on the functions and the scope of use of the embodiments of this application.

As shown in FIG. 7, the electronic device 200 is represented in a form of a general-purpose computing device. Components of the electronic device 200 may include, but are not limited to: at least one processing unit 210, at least one storage unit 220, a bus 230 connecting different system components (including the storage unit 220 and the processing unit 210), a display unit 240, and the like.

The storage unit 220 has program code stored therein, and the program code may be executed by the processing unit 210, so that the processing unit 210 performs the steps of the methods according to the foregoing exemplary implementations of this application.

The storage unit 220 may include a readable medium in the form of a volatile storage unit, for example, a random access memory (RAM) 2201 and/or a cache storage unit 2202, and may further include a read-only memory (ROM) 2203.

The storage unit 220 may further include a program/utility 2204 including a group of (at least one) program modules 2205. Such program modules 2205 include, but are not limited to an operating system, one or more applications, another program module, and program data. Each or a combination of these examples may include implementation of a network environment.

The bus 230 may represent one or more of several types of bus structures, including a storage unit bus or a storage unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any bus structure in a plurality of types of bus structures.

The electronic device 200 may also communicate with one or more external devices 300 (for example, a keyboard, a pointing device, a Bluetooth device, and the like), and may also communicate with one or more devices that enable a user to interact with the electronic device 200, and/or communicate with any device (for example, a router, a modem, and the like) that enables the electronic device 200 to communicate with one or more other computing devices. Such communication may be performed by using an input/output (I/O) interface 250. In addition, the electronic device 200 may further communicate with one or more networks such as a local area network (LAN), a wide area network (WAN), and/or a public network (such as the Internet) through a network adapter 260. The network adapter 260 may communicate with another module of the electronic device 200 through the bus 230. It should be understood that although not shown in the figure, other hardware and/or software modules may be used in combination with the electronic device 200, including, but not limited to microcode, a device driver, a redundancy processing unit, an external disk drive array, a RAID system, a tape drive, a data backup storage system, or the like.

Through the descriptions of the foregoing implementations, a person skilled in the art easily understands that the exemplary implementations described herein may be implemented through software, or may be implemented through software located in combination with necessary hardware. The technical solutions according to the implementations of this application may be implemented in a form of a software product. The software product may be stored in a non-volatile storage medium (which may be a CD-ROM, a USB flash drive, a removable hard disk, or the like) or on the network, including several instructions for instructing a computing device (which may be a personal computer, a server, a network device, or the like) to perform the foregoing method according to the implementations of this application.

The software product may use any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium may be, for example, but not limited to, an electric, magnetic, optical, electromagnetic, infrared, or semi-conductive system, apparatus, or device, or any combination thereof More specific examples (non-exhaustive list) of the readable storage medium may include: an electrical connection having one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any appropriate combination thereof The computer-readable storage medium may include a data signal propagated in a baseband or as part of a carrier, in which computer-readable program code is carried. A data signal propagated in such a way may assume a plurality of forms, including, but not limited to, an electromagnetic signal, an optical signal, or any appropriate combination thereof The readable storage medium may also be any readable medium other than the readable storage medium, which readable medium may send, propagate, or transmit a program configured to be used by or in combination with an instruction execution system, apparatus, or device. The program code embodied on the readable storage medium may be transmitted by using any suitable medium, including, but not limited to, wireless, wired, cable, radio frequency (RF), and the like, or any appropriate combination thereof The program code for executing the operations of the exemplary embodiments of this application may be written by using any combination of one or more programming languages. The programming languages include an object-oriented programming language such as Java and C++, and also include a conventional procedural programming language such as "C" or similar programming languages. The program code may be completely executed on a user computing device, partially executed on user equipment, executed as an independent software package, partially executed on a user computing device and partially executed on a remote computing device, or completely executed on a remote computing device or server. For the case involving a remote computing device, the remote computing device may be connected to a user computing device through any type of network including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (for example, through the Internet by using an Internet service provider).

A person skilled in the art may understand that the foregoing modules may be distributed in the apparatus according to the descriptions of the embodiments, or a corresponding change may be made, so that the modules are distributed in one or more apparatuses different from those in the exemplary embodiments of this application. The modules in the foregoing embodiments may be combined into one module, or split into a plurality of submodul es.

The exemplary embodiments of this application have been specifically shown and described above. It should be understood that this application is not limited to the detailed structures, configurations or implementation methods described herein. On the contrary, this application is intended to cover various modifications and equivalent configurations within the scope of the appended claims.

Claims

CLAIMS1. A determination method for consistency of sending and receiving delays of a differential channel, applicable to a master side or a slave side of the differential channel, the method comprising: calculating a channel delay of the differential channel; adjusting sampling data on both sides of the differential channel to a synchronized state; calculating a variation of the channel delay in real time, and activating determination on consistency of sending and receiving delays of the channel when the variation of the channel delay is greater than a first threshold, to obtain a determination result of the consistency of the sending and receiving delays of the channel; and determining, according to the determination result of the consistency of the sending and receiving delays of the channel, whether to block differential protection.
2. The method according to claim 1, wherein when the variation of the channel delay is greater than the first threshold, a first differential protection pickup threshold is changed to a second differential protection pickup threshold, wherein the second differential protection pickup threshold is greater than the first differential protection pickup threshold.
3. The method according to claim 2, wherein when the determination result of the consistency of the sending and receiving delays of the channel is that the sending and receiving delays of the channel are consistent, after delay confirmation, the second differential protection pickup threshold is changed back to the first differential protection pickup threshold; and when the determination result of the consistency of the sending and receiving delays of the channel is that the sending and receiving delays of the channel are inconsistent, the differential protection is blocked.
4. The method according to claim I, wherein the step of adjusting sampling data on both sides of the differential channel to a synchronized state comprises: calculating an error At between a sampling moment on the master side and a sampling moment on the slave side according to the channel delay after the channel delay is calculated; and maintaining the sampling moment on the master side unchanged, and adjusting the sampling moment on the slave side gradually until At approaches 0.
5. The method according to claim 1, wherein the step of calculating a variation of the channel delay in real time, and activating determination on consistency of sending and receiving delays of the channel when the variation of the channel delay is greater than a first threshold comprises: calculating a channel delay value Td(K) of a current sampling point K in real time, and comparing the channel delay value Td(K) with a channel delay value Td(K-1) of a previous sampling point K-1, to obtain a variation ATd of the channel delay, wherein a calculation formula of the variation ATd is as follows: ATd=abs(Td(K)-Td(K-1)), wherein abs represents finding an absolute value, and the determination on the consistency of the sending and receiving delays of the channel is activated when the variation ATd of the channel delay is greater than the first threshold.
6. The method according to claim 1, wherein the step of activating determination on consistency of sending and receiving delays of the channel comprises: activating, in a case that a single channel is used, a determination method for consistency of sending and receiving delays of the channel in a single-channel mode; or activating, in a case that double channels are used, a determination method for consistency of sending and receiving delays of the channels in a double-channel mode.
7. The method according to claim 6, wherein the activating a determination method for consistency of sending and receiving delays of the channel in a single-channel mode comprises: determining, in a case that neither of protection apparatuses on the both sides of the differential channel picks up, and in addition, both three-phase differential currents 'Din, are greater than a first threshold set value ID,, , both three-phase differential current variations Al,,,TO are greater than a second threshold set value Alpiff," , and both three-phase restrained current variations are less than a third threshold set value AI", , that the sending and receiving delays of the channel are inconsistent, wherein a calculation formula for the three-phase differential current variation and the three-phase restrained current variation is as follows: =1 linrg.(k) na, 12/1 (k) and I,"; ",(k) are respectively a three-phase differential current and a three-phase restrained current of the current sampling point; and 1,",(k -n) and -n) are respectively a three-phase differential current and a three-phase restrained current one cycle before, wherein n is a quantity of sampling points of one cycle
8. The method according to claim 6, wherein the activating a determination method for wherein AI = I consistency of sending and receiving delays of the channels in a double-channel mode comprises: selecting, when a variation ATd of a channel delay of only one of the double channels is greater than the first threshold, a channel whose variation AL of a channel delay is less than or equal to the first threshold as a first channel and the other channel as a second channel, and adjusting sampling data on both sides of the double channels to the synchronized state with the channel delay of the first channel as a reference; and calculating the channel delay of the second channel, wherein the slave side calculates the error At between the sampling moment on the slave side and the sampling moment on the master side according to the channel delay of the second channel, wherein when the error At is less than the second threshold, it is determined that the sending and receiving delays of the second channel are consistent; and when the error At is greater than or equal to the second threshold, it is determined that the sending and receiving delays of the second channel are inconsistent
9. The method according to claim 6, wherein the activating a determination method for consistency of sending and receiving delays of the channels in a double-channel mode comprises: selecting, when both variations AL of channel delays of two channels in the double channels are greater than the first threshold, a channel whose variation of a channel delay is smaller as a first channel and a channel whose variation of a channel delay is larger as a second channel; and and adjusting sampling data on both sides of the first channel to the synchronized state, and then, performing determination on consistency of the sending and receiving delays of the channel on the first channel according to the determination method for consistency of sending and receiving delays of the channel in a single-channel mode.
10. The method according to claim 9, wherein the channel delay of the second channel is calculated when a determination result of the first channel is that the sending and receiving delays of the first channel are consistent, where in the slave side calculates the error At between the sampling moment on the slave side and the sampling moment on the master side according to the channel delay of the second channel, wherein when the error At is less than the second threshold, it is determined that the sending and receiving delays of the second channel are consistent; and when the error At is greater than or equal to the second threshold, it is determined that the sending and receiving delays of the second channel are inconsistent.
11. The method according to claim 9, wherein when it is determined that the sending and receiving delays of the first channel are inconsistent, sampling data on both sides of the double channels is adjusted to the synchronized state with the channel delay of the second channel as a reference, and then, the second channel is determined according to the determination method for consistency of sending and receiving delays of the channel in a single-channel mode.
12. The method according to claim 1, wherein the step of calculating a channel delay of the differential channel comprises: sending, by the slave side, a first frame of message to the master side, and recording a sending moment t55; when receiving the first frame of message, recording, by the master side, a receiving moment id, returning a second frame of message to the slave side at a moment t " _mr, and at the same time, sending a time difference (tins t 1 as message content of the second frame of message to the slave side and receiving, by the slave side, the returned second frame of MS -111f, message at a moment tsr, and extracting the time difference (t t 1 from the second frame of message, wherein the channel delay Td is obtained through the following formula: (t -t55) -(t -t)
13. The method according to claim 12, wherein after the step of adjusting sampling data on both sides of the differential channel to a synchronized state, the method further comprises: calculating a differential current and a restrained current through the following formula according to synchronized current data on the both sides: Wt.() LI) Hk, wherein it, and it, are respectively currents on the master side and the slave side in a (I) phase, and and 1Thasa, are respectively the differential current and the restrained current in the (I) phase.
14. A determination apparatus for consistency of send ng and receiving delays of a differential channel, comprising: a delay calculation module, configured to calculate a channel delay of the differential channel; a synchronization module, configured to adjust sampling data on both sides of the differential channel to a synchronized state; a delay variation monitoring module, configured to calculate a variation of the channel delay in real time, and activate determination on consistency of sending and receiving delays of the channel when the variation of the channel delay is greater than a first threshold and a determination module, configured to perform determination on the consistency of the sending and receiving delays of the channel.
15. An electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable by the processor, wherein the processor implements the steps of the method according to any one of claims 1 to 13 when executing the computer program.
16. A differential protection communication system, comprising the apparatus according to claim 14 and/or the electronic device according to claim 15.