CN112491015B - Time synchronization method suitable for power distribution network - Google Patents
Time synchronization method suitable for power distribution network Download PDFInfo
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- CN112491015B CN112491015B CN202011248190.0A CN202011248190A CN112491015B CN 112491015 B CN112491015 B CN 112491015B CN 202011248190 A CN202011248190 A CN 202011248190A CN 112491015 B CN112491015 B CN 112491015B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J3/00—Time-division multiplex systems
- H04J3/02—Details
- H04J3/06—Synchronising arrangements
Abstract
The invention discloses a clock synchronization method for a medium and low voltage distribution network, which comprises the steps of injecting a time synchronization characteristic signal into a downstream protection device of a medium and low voltage distribution line, collecting a disturbance signal waveform and recording a local time scale at the upstream protection device, transmitting the disturbance signal waveform and marking the local time scale when disturbance starts through a carrier channel by the downstream protection device, and determining the time scale difference of equipment at two ends by the upstream protection device through calculating the correlation degree of two curves. The invention fully considers the current situation and characteristics of the medium and low voltage distribution network, is not influenced by channel delay, does not need to additionally lay a special channel, and realizes the unification of the clock time of two different places and the strict synchronization of the sampling time at low cost.
Description
Technical Field
The invention belongs to the field of distribution automation, and particularly relates to a time synchronization method suitable for a power distribution network.
Background
For line protection, the most efficient approach is referred to as current differential protection. The current differential protection algorithmically requires that the current of each end participating in comparison must be synchronously sampled or obtained by sampling synchronization processing, which is the key point for realizing the current differential protection. The current differential protection can realize zero-second quick break of a fault line, has a simple principle and is not influenced by a voltage transformer. The ping-pong algorithm is usually adopted in the power transmission line or the GPS clock signal is utilized to realize data synchronization, the middle and low voltage distribution network does not have such communication condition, the current situation and the characteristics of the middle and low voltage distribution network are fully considered in the implementation of the current differential protection, the synchronization problem of the current sampling at each end of the line is the technical key for realizing the digital current differential protection, and the existing clock synchronization methods comprise the following steps:
method for adjusting sampling time
One end of the line or equipment protection is a master station, the other end of the line or equipment protection is a slave station, and the master station can freely sample. The method comprises the steps that firstly, a master station sends an information frame, a slave station returns a command and delay time to the master station after receiving the information frame, the master station calculates channel delay and transmits the channel delay to the slave station, and the slave station adjusts the sampling time of the slave station according to the delay. Therefore, the purpose of synchronous sampling of the protective devices at two sides of the line is achieved.
(II) sample data correction method
When the method is adopted, the two-side protection is not divided into a master protection and a slave protection, and each side protection is independently sampled at the same sampling frequency under the control of respective crystal oscillator. Each frame of transmitted data comprises information such as a time tag and current sampling data, and the current sampling data is a current vector subjected to Fourier transform at a certain sampling moment. Under the premise of assuming that the delay of the data receiving channels on the two sides is equal, the channel delay is calculated, further, the sampling deviation of the two sides is solved, the received opposite side current phasor is multiplied by a rotation factor under protection, and corrected synchronous sampling data are obtained.
(III) clock correction method
One end of the two-side protection is a reference end, the other end of the two-side protection is a synchronous end, and the reference end is used for freely sampling. Firstly, the synchronous end sends an information frame, the reference end returns a command and delay time to the synchronous end after receiving the information frame, the synchronous end calculates delta t of the clocks at two sides, the synchronous end corrects the clocks according to a certain ratio according to the step until the delta t is zero, and the clocks at two sides enter a synchronous running state.
(IV) synchronization method based on reference vector
Firstly, a circuit equivalent model is established, two current phasors representing the same quantity at two ends of a circuit are calculated, because the reference phases are different, the two current phasors have phase difference, and the difference of the reference phases is caused by asynchronous sampling of devices at two ends, the phase difference between the two current phasors can be utilized to correct data, and the purpose of sampling synchronization is achieved.
(V) GPS synchronization method
The GPS synchronization method realizes synchronous sampling of devices on two sides through GPS time service information, the sampling clock is synchronized (phase locking) by 1PPS signals once every 1s, the pulse front edge generated by the crystal oscillator and the UTC can be ensured to have the synchronous precision of 1 mu s, the relative error of no more than 2 mu s is formed between the sampling pulses given by the sampling clocks at two ends of the circuit, and the strict synchronization of sampling at two ends is realized.
In the method, a sampling data correction method, a sampling time adjustment method, a clock correction method and an improvement method thereof need to be completed by means of channels. Because the premise of these methods is that the delay of the receiving and transmitting channels is consistent, a dedicated channel or an SDH network is generally adopted for data communication; and realizing data synchronization by adopting a ping-pong algorithm or utilizing a GPS clock signal. These methods can only be applied to transmission lines with perfect communication conditions, and the power distribution network does not have such communication conditions, so that the methods need to be adopted, and the cost needs to be increased greatly.
Disclosure of Invention
The invention aims to provide a time synchronization method suitable for a power distribution network, which can realize the unification of two different-place clock times and the strict synchronization of sampling moments in a medium-low voltage power distribution system at low cost.
According to a first aspect of the present invention, there is provided a time synchronization method for a power distribution network, which is applied to a medium and low voltage power distribution network, and comprises the following steps:
step S10, when detecting a line fault, an upstream protection device in the power distribution network sends a time synchronization starting command to a downstream protection device in the power distribution network;
s11, a downstream protection device receives a time setting starting command, and the on-off resistor generates a high-frequency disturbing signal with a preset frequency;
step S12, after detecting that the disturbing signal forms a disturbing signal waveform, the upstream protection device marks a local time scale and stores the local time scale;
step S13, the downstream protection device forms a time setting characteristic signal waveform after receiving the time setting starting command, marks a local time scale, and transmits the local time scale to the upstream protection device through a carrier information channel after time delay;
step S14, after receiving the time tick characteristic signal waveform, the upstream protection device calculates the correlation with the stored disturbance signal waveform to obtain the relative error of the clocks at the two ends;
and S15, adjusting the sampling time of the upstream protection device or the downstream protection device according to the obtained relative error of the clocks at the two ends.
Preferably, the step S11 specifically includes:
after the downstream protection device receives a time setting request command, a high-frequency disturbance signal with the frequency of 1025Hz is generated through the on-off of the resistor, and the high-frequency disturbance signal is superposed into the power frequency current signal.
Preferably, the step S12 further includes:
the upstream protection device periodically records waveform signals of two cycles in a normal state, continuously stores the disturbance signals of the two cycles when the disturbance signals are detected, forms disturbance signal waveforms of four cycles together with the disturbance signals of the two cycles recorded before the disturbance signals, and marks local time scales of the upstream protection device for the disturbance signal waveforms.
Preferably, the step S13 further includes:
the downstream protection device periodically records waveform signals of two cycles in a normal state, records the waveform signals of the two cycles at the moment of receiving a time synchronization starting command, and forms time synchronization characteristic signals of four cycles together with the waveform signals of the two cycles recorded before the time synchronization starting command is received; and marking the signal with a local time scale of an upstream protection device and a downstream protection device, and transmitting the signal to the upstream protection device through a carrier information channel after delaying.
Preferably, the step S14 further includes:
step S140, determining a calculation formula of correlation between the disturbance signal waveform and the time tick characteristic signal waveform stored in the upstream protection device as follows:
wherein, x (m) is a disturbance signal waveform, the center of a window is the disturbance occurrence time t, the fixed window length is 2T, and T is the period of the high-frequency disturbance signal waveform; y (m) is a time setting characteristic signal waveform; r xy (k) The correlation function of x (m), y (m + k) on time delay k, namely the correlation coefficient;
step S141, scanning the time-alignment characteristic signal waveform y (m), calculating R xy (k) Obtaining the value of k when the maximum value is obtained, and assuming that k = delta t at the moment, the delta t represents the time difference between the clocks of the two terminals;
wherein, when Δ t >0, it indicates that the clock of the upstream protection device is ahead of the clock of the downstream protection device; when Δ t <0, it indicates that the upstream protection device clock lags the downstream protection device clock.
Preferably, the step S15 further includes:
and adjusting the next sampling time of the upstream protection device or the downstream protection device according to the calculated relative error of the clocks at the two ends, so that the upstream protection device and the downstream protection device are stably synchronized.
Preferably, the step S15 further includes:
and according to the calculated relative error of the clocks at the two ends, adopting a stable adjustment coefficient to gradually adjust the next sampling time of the upstream protection device or the downstream protection device so as to stably synchronize the upstream protection device and the downstream protection device.
The implementation of the invention has the following beneficial effects:
the embodiment of the invention provides a time synchronization method suitable for a power distribution network, which reasonably utilizes the characteristics of a medium and low voltage power distribution network, a trunk line in the medium and low voltage power distribution network is short, the propagation time of disturbance signal electromagnetic waves can be ignored on such a long line, and a line upstream protection device can detect the disturbance signal without delay, so that the method does not need to rely on a communication channel and does not need to add a special time synchronization device, and compared with the prior art, the method can be more suitable for the medium and low voltage power distribution network environment;
meanwhile, the method of the invention can complete clock synchronization only by using a line carrier communication channel without laying an additional special channel, thereby reducing the cost; the condition of wide application in the medium and low voltage distribution network is met, the application of differential protection in the medium and low voltage distribution network is promoted, and the blank of line protection of the medium and low voltage distribution network trunk is filled;
in addition, the invention can realize higher synchronization precision of the clock, is convenient to realize high-frequency disturbance on the on-off of the resistor due to lower voltage grade in the medium and low voltage distribution network, and is more convenient to adjust the resistance value of the resistor under different low voltage distribution environments.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is within the scope of the present invention for those skilled in the art to obtain other drawings based on the drawings without inventive exercise.
Fig. 1 is a schematic main flow chart of an embodiment of a time synchronization method for a power distribution network according to the present invention;
fig. 2 is a schematic diagram of a distribution network area structure according to the present invention;
FIG. 3 is a comparison graph of the time tick signature waveform and the disturbance signal waveform according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
For those skilled in the art to more clearly understand the objects, technical solutions and advantages of the present invention, the following description will be further provided in conjunction with the accompanying drawings and examples.
As shown in fig. 1, which is a schematic main flow chart illustrating an embodiment of a method for time synchronization of a power distribution network according to the present invention, and is shown in fig. 2 and fig. 3, in this embodiment, the method is applied to a medium-low voltage power distribution network, and includes the following steps:
step S10, when detecting a line fault, an upstream protection device in the power distribution network sends a time setting starting command to a downstream protection device in the power distribution network; specifically, as illustrated in fig. 2 below, the communication conditions in the medium and low voltage power distribution network are not perfect, for example, a main line in the medium and low voltage power distribution network is short, specifically, the upstream protection device P21 and the downstream protection device P41 are illustrated as an example, and the upstream protection device P21 sends a start time tick command to the downstream protection device;
s11, a downstream protection device receives a time setting starting command, and the on-off resistor generates a high-frequency disturbing signal with a preset frequency; specifically, after receiving the request time setting command, the downstream protection device P41 generates a high-frequency disturbance signal with a frequency of 1025Hz by switching on and off the resistor, and superimposes the high-frequency disturbance signal on the power frequency current signal.
Step S12, after detecting that the disturbing signal forms a disturbing signal waveform, the upstream protection device marks a local time scale and stores the local time scale; specifically, the upstream protection device P21 periodically records waveform signals of two cycles in a normal state; because the length of the low-voltage distribution line is short, the propagation time of electromagnetic waves can be ignored on such a long line, the upstream protection device P21 will immediately detect the disturbing signal, when the disturbing signal is detected, the disturbing signals of two cycles are continuously stored, the disturbing signal waveform of four cycles is formed together with the disturbing signals of two cycles recorded before the disturbing signal, and the local time scale of the upstream protection device is marked on the disturbing signal waveform.
Step S13, the downstream protection device forms a time setting characteristic signal waveform after receiving the time setting starting command, marks a local time scale, and transmits the local time scale to the upstream protection device through a carrier information channel after time delay; specifically, the downstream protection device P41 periodically records two cycle waveform signals in a normal state, records two cycle waveform signals at the time of receiving the start time setting command, and forms a four cycle time setting characteristic signal together with the two cycle waveform signals recorded before receiving the start time setting command; and time-stamping the signal to the local time scale of the upstream and downstream protection devices and delaying the signal (such as t) m ) And transmitting the data to an upstream protection device through a carrier information channel.
Step S14, after receiving the time tick characteristic signal waveform, the upstream protection device calculates the correlation with the stored disturbance signal waveform to obtain the relative error of the clocks at the two ends;
it can be understood that, at this time, the upstream protection device stores the disturbance signal waveform and the time tick characteristic signal waveform at the same time, and since the boundary of two sampled waveforms is fuzzy, the starting point cannot be determined, so that the upstream protection device performs correlation calculation on the detected disturbance signal and the time tick characteristic signal sent by carrier communication.
Wherein, the correlation analysis is a statistical analysis method for researching the correlation between random variables. Deterministic signals can be considered as a special case of random signals that are stationary and ergodic, so correlation analysis can be used to determine how similar two waveforms are. Let x (t), y (t) be two continuous functions with finite energy, their correlation operations are defined as follows:
in the formula, R xy And (tau) is a correlation function of x (t) and y (t-tau) on the time delay tau, namely a correlation coefficient.
The waveform of the disturbance signal and the waveform of the time-setting characteristic signal collected by the upstream protection device are both discrete signals, and for the discrete signals x (m) and y (m), a correlation function is defined as:
in the formula, k is the sampling point number.
The correlation operation is equivalent to translating one function and then scanning the other function, and the degree of similarity is measured by the cross-correlation function of the two functions, and the value of the correlation function is the maximum where the degree of similarity between the two functions is the maximum. Calculating a tau-make correlation coefficient R xy And (tau) is maximum, and the waveform x (t) at the moment is just aligned with y (t) after being shifted by tau, namely the time difference of the two waveforms is obtained.
Therefore, in an embodiment, referring to fig. 3, the step S14 further includes:
in step S140, a calculation formula (3) for determining a correlation between the disturbance signal waveform and the time-tick characteristic signal waveform stored in the upstream protection device is as follows:
wherein x (m) is the waveform of the disturbance signal, the center of the window is the disturbance occurrence time t, the fixed window length is 2T, T is the period of the waveform of the high-frequency disturbance signal, namely
y (m) is a time setting characteristic signal waveform; r is xy (k) The correlation function (also called correlation coefficient) of x (m) and y (m + k) on the time delay k can reflect the similarity degree of the two functions under different offsets;
step S141, scanning the time characteristic signal waveform y (m) and calculating R xy (k) Obtaining the value of k when the maximum value is obtained, wherein the two wave forms are most similar, and supposing that k = delta t at the moment, the delta t represents the time difference between the two terminal clocks;
wherein, when Δ t >0, it indicates that the clock of the upstream protection device is ahead of the clock of the downstream protection device; when Δ t <0, it indicates that the upstream protection device clock lags the downstream protection device clock.
And S15, adjusting the sampling time of the upstream protection device or the downstream protection device according to the obtained relative error of the clocks at the two ends.
In particular, the downstream protection device may modify its own time scale according to the upstream protection device and vice versa; the time scales of both sides can be saved in the upstream and downstream, and the corresponding relation of the time scales of both sides can be memorized.
In some examples, the next sampling time of the upstream protection device or the downstream protection device may be adjusted according to the calculated relative error of the two-terminal clocks, so that the upstream protection device and the downstream protection device are stably synchronized.
For example, assume a two-sided time-scale approach with the time-scale of the upstream protection device, Δ t>When 0, it indicates that the clock of the upstream protection device is ahead of the clock of the downstream protection device by Δ t<A0 indicates that the upstream protection device clock lags the downstream protection device clock. In order to synchronously sample the two end devices, the next sampling moment of the downstream protection device is adjusted to be as follows:t i+1 ＝(t i +T s ) - Δ t. Sampling interval of T s Controlled by a crystal oscillator.
In some examples, the step S15 further includes:
and according to the calculated relative error of the clocks at the two ends, adopting a stable adjustment coefficient to gradually adjust the next sampling time of the upstream protection device or the downstream protection device so as to stably synchronize the upstream protection device and the downstream protection device.
For example, for stable regulation, the following formula is often used for regulation:
wherein 2 n And in order to stabilize the adjustment coefficient, the adjustment is carried out step by step, and after the upstream and the downstream are stably synchronized, the sampling data can be transmitted to the opposite side.
Therefore, in order to keep the clocks on both sides consistent frequently and the sampling time consistent in real time, the upstream and downstream protection devices need to perform calibration and sampling synchronization control at regular time (a certain number of sampling intervals) (depending on the frequency difference of the crystal oscillators on both sides).
The implementation of the invention has the following beneficial effects:
the embodiment of the invention provides a time synchronization method suitable for a power distribution network, which reasonably utilizes the characteristics of a medium and low voltage power distribution network, a trunk line in the medium and low voltage power distribution network is shorter, the propagation time of disturbance signal electromagnetic waves can be ignored on such a long line, and a line upstream protection device can detect the disturbance signal without delay, so that the dependence on a communication channel is not needed, a special time synchronization device is not needed, and compared with the prior art, the time synchronization method is more suitable for the medium and low voltage power distribution network environment;
meanwhile, the method of the invention can complete clock synchronization only by using a line carrier communication channel without laying an additional special channel, thereby reducing the cost; the condition of wide application in the medium and low voltage distribution network is met, the application of differential protection in the medium and low voltage distribution network is promoted, and the blank of line protection of the medium and low voltage distribution network trunk is filled;
in addition, the invention can realize higher synchronization precision of the clock, is convenient to realize high-frequency disturbance on the on-off of the resistor due to lower voltage level in the medium and low voltage distribution network, and is more convenient to adjust the resistance value of the resistor under different low voltage distribution environments.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Claims (7)
1. A time synchronization method suitable for a power distribution network is applied to a medium and low voltage power distribution network and is characterized by comprising the following steps:
step S10, when detecting a line fault, an upstream protection device in the power distribution network sends a time synchronization starting command to a downstream protection device in the power distribution network;
s11, a downstream protection device receives a starting time setting command, and the on-off resistor generates a high-frequency disturbing signal with a preset frequency;
step S12, after detecting that the disturbing signal forms a disturbing signal waveform, the upstream protection device marks a local time scale and stores the local time scale;
step S13, the downstream protection device forms a time setting characteristic signal waveform after receiving the time setting starting command, marks a local time scale, and transmits the local time scale to the upstream protection device through a carrier information channel after time delay;
step S14, after receiving the time tick characteristic signal waveform, the upstream protection device calculates the correlation with the stored disturbance signal waveform to obtain the relative error of the clocks at the two ends;
and S15, adjusting the sampling time of the upstream protection device or the downstream protection device according to the obtained relative error of the clocks at the two ends.
2. The method according to claim 1, wherein the step S11 is specifically:
after the downstream protection device receives the request time setting command, a high-frequency disturbance signal with the frequency of 1025Hz is generated by switching on and off the resistor, and the high-frequency disturbance signal is superposed into the power frequency current signal.
3. The method of claim 2, wherein the step S12 further comprises:
the upstream protection device periodically records waveform signals of two cycles in a normal state, continuously stores the disturbance signals of the two cycles when the disturbance signals are detected, forms disturbance signal waveforms of four cycles together with the disturbance signals of the two cycles recorded before the disturbance signals, and marks local time scales of the upstream protection device for the disturbance signal waveforms.
4. The method of claim 3, wherein the step S13 further comprises:
the downstream protection device periodically records waveform signals of two cycles in a normal state, records the waveform signals of the two cycles at the moment of receiving a time synchronization starting command, and forms time synchronization characteristic signals of four cycles together with the waveform signals of the two cycles recorded before the time synchronization starting command is received; and marking the signal with a local time scale of an upstream protection device and a downstream protection device, and transmitting the signal to the upstream protection device through a carrier information channel after time delay.
5. The method of claim 4, wherein the step S14 further comprises:
step S140, determining a calculation formula for correlating the disturbance signal waveform and the time tick signature signal waveform stored in the upstream protection device as follows:
wherein, x (m) is a disturbance signal waveform, the center of a window is the disturbance occurrence time t, the fixed window length is 2T, and T is the period of the high-frequency disturbance signal waveform; y (m) is a time setting characteristic signal waveform; r xy (k) Is a correlation function of x (m), y (m + k) on a time delay k;
step S141, time-aligned characteristic signal waveformy (m) are scanned and R is calculated xy (k) Obtaining the value of k when the maximum value is obtained, and assuming that k = delta t at the moment, the delta t represents the time difference between the clocks of the two terminals;
wherein, when Δ t >0, it indicates that the clock of the upstream protection device is ahead of the clock of the downstream protection device; when Δ t <0, it indicates that the upstream protection device clock lags the downstream protection device clock.
6. The method of claim 5, wherein the step S15 further comprises:
and adjusting the next sampling time of the upstream protection device or the downstream protection device according to the calculated relative error of the clocks at the two ends, so that the upstream protection device and the downstream protection device are stably synchronized.
7. The method of claim 6, wherein the step S15 further comprises:
and gradually adjusting the next sampling time of the upstream protection device or the downstream protection device by adopting a stable adjustment coefficient according to the calculated relative error of the clocks at the two ends, so that the upstream protection device and the downstream protection device are stably synchronized.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002095977A1 (en) * | 2001-05-23 | 2002-11-28 | Diseño De Sistemas En Silicio, S.A. | Synchronisation method for the uplink channel in a point-to-multipoint communication with ofdm modulation |
| CN104659809A (en) * | 2015-01-26 | 2015-05-27 | 国网浙江海盐县供电公司 | Anti-islanding grid-connection intelligent switch protection method for distributed type power supply system and grid-connection intelligent switch device |
| CN106099879A (en) * | 2016-08-09 | 2016-11-09 | 深圳供电局有限公司 | A kind of flexible direct current distribution network line differential protection system and differential protection implementation method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103827678B (en) * | 2011-06-30 | 2017-04-26 | Abb研究有限公司 | Method for distributed waveform recording in a power distribution system |
-
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002095977A1 (en) * | 2001-05-23 | 2002-11-28 | Diseño De Sistemas En Silicio, S.A. | Synchronisation method for the uplink channel in a point-to-multipoint communication with ofdm modulation |
| CN104659809A (en) * | 2015-01-26 | 2015-05-27 | 国网浙江海盐县供电公司 | Anti-islanding grid-connection intelligent switch protection method for distributed type power supply system and grid-connection intelligent switch device |
| CN106099879A (en) * | 2016-08-09 | 2016-11-09 | 深圳供电局有限公司 | A kind of flexible direct current distribution network line differential protection system and differential protection implementation method |
Non-Patent Citations (2)
| Title |
|---|
| Data Sampling System with High Speed and High Timing Synchronization Precision for Power Line Fault Position Detection based on Dual Ports Traveling Wave Distance Measurement Method;Zhang Donglai等;《2005 IEEE/PES Transmission & Distribution Conference & Exposition: Asia and Pacific》;20051231;第1-4页 * |
| OFDM在配电网高速数据通信中的应用;梅欣等;《电力系统通信》;20050410(第04期);第20-22页 * |
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