CN117277584B - Multi-terminal electric quantity protection synchronization method and system integrating electric quantity and clock information - Google Patents
Multi-terminal electric quantity protection synchronization method and system integrating electric quantity and clock information Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
- H02J13/00006—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
- H02J13/00022—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment using wireless data transmission
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0061—Details of emergency protective circuit arrangements concerning transmission of signals
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
- H02J13/00032—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for
- H02J13/00036—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for the elements or equipment being or involving switches, relays or circuit breakers
- H02J13/0004—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for the elements or equipment being or involving switches, relays or circuit breakers involved in a protection system
Abstract
The invention discloses a multi-terminal electric quantity protection synchronization method and a system integrating electric quantity and clock information, belonging to the technical field of multi-terminal electric quantity protection, wherein the method comprises the following steps: when external time synchronization is normal, the protection device samples, determines synchronous reference electric quantity and receives external second pulse; the protection device adjusts sampling time according to the received second pulse, performs cycle and sampling point coding, and realizes the data synchronization of the protection device based on an absolute time scale by adopting cycle numbers and sampling sequence numbers; and when external time synchronization is abnormal, the protection device for processing the time synchronization abnormality carries out sampling synchronization based on the time deviation variation of the sampling forward zero crossing point. The invention fuses synchronous reference electric quantity and clock information, and synchronizes based on absolute time scale when external time synchronization is normal, and synchronizes based on sampling forward zero crossing point time deviation variation when external time synchronization is abnormal, thereby maximally providing time synchronization reliability of the protection device.
Description
Technical Field
The invention belongs to the technical field of multi-terminal electric quantity protection, and relates to a multi-terminal electric quantity protection synchronization method and system integrating electric quantity and clock information.
Background
At present, the distribution network mainly adopts overcurrent protection, and this protection relies on action value and action time's cooperation step by step to realize distribution network fault isolation function, and it only needs to use the electric quantity of protection installation department, and the principle is simple, realizes conveniently. Along with the large number of accesses of distributed power supplies, the power distribution network is changed from a traditional single-ended power supply to a multi-ended power supply, the original power distribution network overcurrent protection only considers the single-ended power supply matching relation, and the power distribution network operation modes are flexible and changeable, so that the overcurrent protection misoperation and the refusal operation risks are obviously increased. Meanwhile, the reliability requirement of the urban power distribution network is higher and higher, the fault time is limited, the overcurrent protection can only position faults according to 1-2 fault sections, the fineness is insufficient, the fault isolation time is longer, and the construction requirement of the high-reliability power distribution network is not met. In this regard, protection principles based on multi-terminal electric power, such as differential protection, are required to be introduced into the power distribution network, so as to solve the problem of inadaptation of protection after the high-proportion distributed power supply is accessed, and improve the power supply reliability of the power distribution network.
In order to meet the calculation requirement of the multi-terminal electric quantity protection principle, electric quantities of different terminals at the same moment need to be synchronously calculated, and a communication channel for transmitting the electric quantities and a synchronization technology for carrying out time identification on information are needed. Because of the wide distribution network, the optical fiber laying is difficult, and the wireless communication technology (such as 5G) is used for bearing the multi-terminal electric quantity protection of the distribution network, which becomes the current development direction.
For the wireless communication technology, the end-to-end communication delay is uncertain and frequently changed, the receiving and transmitting delays are inconsistent, and the synchronization of different end information is difficult to be carried out through the channel delay of information transmission, and only the absolute time stamp can be given to an external time setting device, so that the transmission information is transmitted to other sides after being time stamped, and the receiving side calculates the time stamp of the information sent by different sending sides and the time of the device. The reliability of protection is significant for the safe operation of the power grid, and the power grid should operate under the normal operation of relay protection. In this mode of operation, the protection function will be heavily dependent on the normal operation of the external clock. The external clock may be affected by the working state of the time setting device, the external environment, the weather state and other factors, and the abnormal external time setting function causes the multi-terminal electric quantity protection function to be lost, which will significantly affect the protection reliability.
Disclosure of Invention
In order to solve the defects in the prior art, the invention provides a multi-terminal electric quantity protection synchronization method and system for fusing electric quantity and clock information, which are used for fusing synchronous reference electric quantity and clock information, synchronizing the clock information based on absolute time marks when external time synchronization is normal, synchronizing the time deviation variation based on sampling forward zero crossing points when external time synchronization is abnormal, and can provide time synchronization reliability of a protection device to the greatest extent.
The invention adopts the following technical scheme.
A multi-terminal electric quantity protection comprehensive synchronization method integrating electric quantity and clock information comprises the following steps:
step 1, aiming at multi-terminal electric quantity protection, when external time synchronization is normal, the protection devices on two sides of any one primary device respectively sample according to fixed sampling beats, determine synchronous reference electric quantity, and simultaneously receive second pulses with absolute time marks, which are given by the external time synchronization device;
step 2, the protection devices on two sides of any one primary equipment adjust sampling time according to the received second pulse, electric quantity sampling is carried out when the second pulse reaches the whole second, cyclic frequency and sampling point coding are carried out, cyclic frequency numbers and sampling sequence numbers are obtained, and the data synchronization of the protection devices based on absolute time marks is realized by adopting the cyclic frequency numbers and the sampling sequence numbers;
step 3, when one side protection device does not receive the external second pulse within a set time period, confirming that the external second pulse is in an external time-setting abnormal state from the next cycle, processing according to the time-setting abnormal state, transmitting the time-setting abnormal state to the opposite side protection device, and processing according to the time-setting abnormal state by the opposite side protection device;
and 4, based on the synchronous reference electrical quantity determined in the step 1, sampling synchronization is carried out according to the time deviation variable quantity of the sampling forward zero crossing point by the protection device for time synchronization exception processing.
Preferably, in step 1, for multi-terminal electric quantity protection, protection devices on two sides of any one primary device sample according to a fixed sampling beat, and determine synchronous reference electric quantity, which specifically includes:
when external time synchronization is normal, after the protection device is electrified, the protection devices on two sides of any one primary device independently sample according to fixed sampling frequency and sampling interval;
when the protection device detects normal input of any one phase voltage or any two phase voltage, the protection device continuously detects the phase voltage or the line voltage which is preferentially selected by taking the normally input phase voltage or two phase voltage as a priority principle, and sends the result of the phase voltage or two phase line voltage which is preferentially selected at the self side to the opposite side, and the two sides determine the same phase voltage or two phase line voltage as synchronous reference electric quantity to be used for subsequent sampling synchronization based on the time deviation variation of the sampling forward zero crossing point.
Preferably, in step 2, the protection device a at one side of any one of the primary electric power devices samples the electric quantity when the second pulse reaches the whole second of the protection device, records the sampled value acquired at the moment, performs cycle and sampling point coding to obtain cycle numbers and sampling serial numbers, and then sends the acquired sampled value and cycle numbers and sampling serial numbers thereof to the opposite side protection device B as sampling data;
after receiving the sampling data sent by the opposite-side protection device A, the protection device B acquires the corresponding serial number cycle number and sampling serial number of the sampling value in the sampling data, addresses and maps the sampling value in the historical buffer zone data of the side according to the cycle number and the sampling serial number, and finds the sampling value corresponding to the same cycle number and the sampling serial number of the side so as to complete the synchronization of the two-side protection device data based on the absolute time scale.
Preferably, the set period of time in step 3 is 2 cycles.
Preferably, in step 4, the sampling synchronization based on the sampling forward zero crossing time deviation variation refers to:
protection device for processing time-lapse abnormality, and method for calculating and sampling forward zero crossing time deviation variation delta T based on synchronous reference electric quantity 0 If the time deviation variation delta T of the positive zero crossing point is sampled 0 If the sampling time exceeds the set threshold, the sampling time is adjusted to make DeltaT 0 The set threshold is not exceeded, wherein the sampling positive zero crossing point refers to the actual zero crossing point of the electric quantity in the case that the sampling value at the current moment is greater than or equal to 0 and the sampling value at the previous moment is less than 0.
Preferably, in step 4, when the second pulse signal is received again, the synchronization signal is considered to be recovered, after the synchronization signal is recovered, the protection device starts timing, when the synchronization signal recovery time exceeds the preset time Tr, the protection device switches to the protection device data synchronization strategy based on the absolute time scale from the next second pulse when the synchronization signal recovery time exceeds the preset time Tr, and the step 2 is returned.
Preferably, the forward zero crossing time deviation variation delta T is calculated once per cycle 0 The calculation formula is as follows:
wherein,for synchronous reference of electric quantity->The cycle number of the sampling signal is sq, and the sampling sequence number is i; and sq is the synchronous reference electrical quantity +.>The current cycle number of the positive zero crossing, i is the first sampling sequence number after the positive zero crossing;
for synchronous reference of electric quantity->The cycle number of the sampling signal is sq-1, and the sampling sequence number is i;
the frequency voltage Fourier value is the frequency number sq;
as a complex argument function;
the difference between the angle corresponding to the sampling time with the cycle number of sq and the sampling number of i and the angle corresponding to the sampling time with the cycle number of sq-1 and the sampling number of i.
Preferably, the forward zero crossing time deviation variation delta T is calculated once per second 0 The calculation formula is as follows:
wherein,for synchronous reference of electric quantity->The cycle number of (1) is sq, the sampling number is i, and sq is synchronous reference electric quantity +.>The cycle number of the positive zero crossing is i is the first sampling sequence number after the positive zero crossing, and the cycle number before one second of the cycle number sq is +.>；
For synchronous reference of electric quantity->Is>The instantaneous sampling value with the sampling sequence number of i;
the frequency voltage Fourier value is the frequency number sq;
as a complex argument function;
the difference between the angle corresponding to the sampling time with the cycle number of sq and the sampling number of i and the angle corresponding to the sampling time with the cycle number of sq-1 and the sampling number of i.
Preferably, the positive zero crossing time deviation variation delta T 0 Employed in calculationsThe judgment standard is that the normal voltage value is as follows:
if the electrical quantity is synchronously referencedIf the phase voltage is phase voltage, the three-phase effective value of the phase voltage is rated value, and the phase difference is a normal voltage value when 120 degrees;
if the electrical quantity is synchronously referencedThe effective value of the line voltage is rated value, and the effective value is normal voltage value when the phase difference is 120 degrees.
Preferably, in step 4, when the voltage of a certain phase or the voltage of an inter-phase meets the abrupt change criterion, the protection device does not calculate the forward zero-crossing time deviation change amount Δt any more 0 And exiting sampling synchronization based on the sampling forward zero crossing time deviation variable quantity, wherein the abrupt change quantity criterion is as follows:
wherein,uxfor sampling values of arbitrary phase voltages or line voltages, subscriptsqIndicating the current sample number, subscriptq-1 represents the previous sample number, subscriptq-2 represents the first two sample sequence numbers,ux △set the threshold is determined for the voltage step-up amount.
A multi-terminal electrical quantity protection synchronization system that fuses electrical quantity and clock information, comprising:
the sampling module is used for sampling protection devices on two sides of any one primary equipment respectively according to fixed sampling beats when external time setting is normal aiming at multi-terminal electric quantity protection, determining synchronous reference electric quantity, and receiving second pulses with absolute time marks, which are given by the external time setting device;
the first synchronization module is used for adjusting sampling time by the protection devices at two sides of any one primary device according to the received second pulse, sampling electrical quantity when the second pulse reaches the whole second, and performing cycle and sampling point coding to obtain cycle numbers and sampling sequence numbers, and realizing data synchronization of the protection devices based on absolute time marks by adopting the cycle numbers and the sampling sequence numbers;
the abnormality judging module is used for confirming that the external time-setting abnormality state is in the time-setting abnormality state from the next cycle when the external second pulse is not received by one side protection device within a set time period, transmitting the time-setting abnormality state to the opposite side protection device, and processing the time-setting abnormality by the opposite side protection device;
and the second synchronization module is used for carrying out sampling synchronization on the protection device for processing time synchronization abnormality based on the determined synchronous reference electrical quantity and the sampling forward zero crossing time deviation variation.
The invention has the beneficial effects that compared with the prior art:
according to the invention, aiming at multi-terminal electric quantity protection, two-stage coding of an electric quantity sampling sequence, a forward zero crossing time deviation variable quantity and a mutation quantity criterion are provided, and voltage cycle sampling point counting and forward zero crossing time deviation variable quantity are completed during normal operation; when the external clock normally works, the synchronization precision can be ensured to the greatest extent through the synchronization of the absolute time scale and the sampling sequence, and the high-precision synchronization requirement of the multi-terminal electric quantity protection of the power distribution network under the complex wireless communication based on 5G and the like is met; when the external clock is abnormal, the method is switched to a synchronization method adopting a voltage forward zero crossing point and a cycle sampling sequence, the synchronization of multi-terminal electric quantity protection is realized by combining the time deviation variation quantity of the forward zero crossing point and the abrupt change quantity criterion, the synchronization requirement of the multi-terminal electric quantity protection of the power distribution network under the complex wireless communication based on 5G and the like is met, the multi-terminal electric quantity protection can continue to operate, and the synchronization link is not a short plate of the reliability of the multi-terminal electric quantity protection of the power distribution network.
Drawings
FIG. 1 is a flow chart of a multi-port electrical protection synchronization method of the present invention;
FIG. 2 is a schematic diagram of synchronization based on cycle number and sampling number;
FIG. 3 is a schematic diagram of a forward zero-crossing time offset;
FIG. 4 is a synchronous schematic diagram based on forward zero-crossing time offset variation adjustment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. The embodiments described herein are merely some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art without making any inventive effort, are within the scope of the present invention.
The embodiment 1 of the invention provides a multi-terminal electric quantity protection synchronization method integrating electric quantity and clock information, wherein for single-terminal electric quantity protection, only the electric quantity of the installation place of local terminal equipment is required to be collected for protection calculation; the multi-terminal electric quantity protection not only collects the electric quantity of the local terminal, but also collects the electric quantity incoming line protection calculation of the opposite terminal of the line in a communication mode, and the possible multi-branch condition of the line is considered, so that the multi-terminal coverage is adopted in the most condition. Specifically, the method comprises the following steps:
step 1, aiming at multi-terminal electric quantity protection, when external time synchronization is normal, the protection devices on two sides of any one primary device respectively sample according to fixed sampling beats, determine synchronous reference electric quantity, and simultaneously receive second pulses with absolute time marks, which are given by the external time synchronization device;
further preferably, for multi-terminal electric quantity protection, the protection devices on two sides of any one primary device sample according to a fixed sampling beat and determine synchronous reference electric quantity, which specifically includes:
when external time synchronization is normal, after the protection device is electrified, the protection devices on two sides of any one primary device independently sample according to fixed sampling frequency and sampling interval; where the sampling frequency and sampling interval are uniform on both sides, it is common practice to have 24 points per cycle (1200 HZ). Different manufacturers of data transmission frequencies have different methods, and each point is independently transmitted (frequency is 1200 HZ), and also several points are combined into 1 frame message to be transmitted together (frequency is 1200/NHZ).
When the protection device detects that any one phase voltage or any two phase voltage is established (namely normal input, the voltage value (amplitude and phase) meets the state of normal operation), the protection device continuously detects the phase voltage or the line voltage which is preferentially selected by taking the established phase voltage A phase or AB phase voltage as a priority principle, and sends the result of the phase voltage or the line voltage which is preferentially selected at the side to the opposite side, and the two sides determine the same phase voltage or the line voltage as synchronous reference electric quantity to be used for subsequent sampling synchronization based on the time deviation change quantity of the sampling forward zero crossing point. It should be noted that the synchronous reference electric quantity (reference voltage) may be a phase voltage (A, B or C) or a line voltage (AB, BC, CA), and in view of convenience and habit of description, the present invention is implemented by using the a phase or the AB phase as the reference voltage.
Step 2, the protection devices on two sides of any one primary equipment adjust sampling time according to the received second pulse, electric quantity sampling is carried out when the second pulse reaches the whole second, cyclic frequency and sampling point coding are carried out, cyclic frequency numbers and sampling sequence numbers are obtained, and the data synchronization of the protection devices based on absolute time marks is realized by adopting the cyclic frequency numbers and the sampling sequence numbers;
1) The protection device A at one side of any one electric power primary equipment samples the electric quantity when the second pulse reaches the whole second of the protection device, records the sampling value acquired at the moment, carries out cycle and sampling point coding to obtain cycle numbers and sampling serial numbers, and then sends the acquired sampling value and the cycle numbers and the sampling serial numbers thereof to the opposite side protection device B as sampling data;
each sampling point can pass throughS AB To show that, by means of the method,Athe number of the frequency is given to the number,Bfor sampling sequence number, when the protecting device transmits data, the sampling point is corresponding toS AB And transmitted to the opposite side protection device.
The number sequence of each second A is 0 and 1 …, the number sequence of each cycle B is 0 and 1 … N-1 assuming that the number of sampling points of each cycle is N, and then the sampling data composed of the numbers and the corresponding sampling values are sent to the protection device B on the opposite side of the protection device A.
2) After receiving the sampling data sent by the opposite-side protection device A, the protection device B acquires the corresponding serial number cycle number and sampling serial number of the sampling value in the sampling data, addresses and maps the sampling value in the historical buffer zone data of the side according to the cycle number and the sampling serial number, and finds the sampling value corresponding to the same cycle number and the sampling serial number of the side so as to complete the synchronization of the two-side protection device data based on the absolute time scale.
For example, as shown in fig. 2, in the differential protection, SM0 is a sampling value with sampling number 0 at the whole second time of M-side protection in fig. 2, and SM1, SMN correspond to sampling values with sampling numbers 1, 2, N, respectively. In fig. 2, VM0 is a transmission value when the sampling sequence number is 0, and the transmission value may be an original sampling value or a calculated value according to different protection principles; VM1, VM2, VMN correspond to the transmission values with sampling numbers of 1, 2, N respectively, and are consistent with the N side, and can be original sampling values or calculated values.
Taking the M side as an example, after receiving the data sent by the N side, the data on both sides is synchronized by acquiring the corresponding sampling sequence number in the data, addressing and mapping the data according to the historical buffer database of the sampling sequence number on the side, and finding the value under the same sequence number on the side.
The traditional sampling synchronization method based on absolute time scale is to start numbering after the whole second pulse signal is reached, and renumber every second, which usually adopts primary coding and codes 4000 points every second; the invention considers that under the condition of losing the synchronous signal, the synchronous is carried out through the forward zero-crossing sampling phase angle, and as 50 cycles exist per second, the sampling points in different cycles can have consistency, and the confusion can exist. Once confused, the sampling points will differ by at least one cycle (20 ms), which is very detrimental to safety. Therefore, the invention divides the electric quantity sampling sequence into two-stage codes, samples 50 cycles per second, numbers the cycles first, and then numbers the sampling point serial numbers in a single cycle to obtain the cycle numbers and the sampling serial numbers.
The history buffer stores the electrical values required for the protection logic calculation, including current, voltage, breaker position, etc., which together with the information transmitted by the opposite side protection device, complete the protection logic calculation.
In general, no matter what communication mode is adopted for transmitting the protection information, the transmission delay is several milliseconds to several hours milliseconds, so that the receiving side protection device and the transmitting side protection device can only be the same second or the next second, and the relation between sampling periods (1 second) can represent absolute time marks. Meanwhile, the data transmission message of the device also has UTC time information content, so that the sampling period can be checked.
Step 3, when one side protection device does not receive the external second pulse within a set time period, confirming that the external second pulse is in an external time-setting abnormal state from the next cycle, processing according to the time-setting abnormal state, transmitting the time-setting abnormal state to the opposite side protection device, and processing according to the time-setting abnormal state by the opposite side protection device;
further preferably, the time period Ts is set, and in order to ensure reliability, ts may take 2 cycles, that is, 40ms.
And 4, based on the synchronous reference electrical quantity determined in the step 1, sampling synchronization is carried out according to the time deviation variable quantity of the sampling forward zero crossing point by the protection device for time synchronization exception processing.
In step 4, the sampling synchronization based on the sampling forward zero crossing time deviation variation refers to:
protection device for processing time-lapse abnormality, and method for calculating and sampling forward zero crossing time deviation variation delta T based on synchronous reference electric quantity 0 If the time deviation variation delta T of the positive zero crossing point is sampled 0 If the sampling time exceeds the set threshold, the sampling time is adjusted to make DeltaT 0 The set threshold is not exceeded, wherein the sampling positive zero crossing point refers to the actual zero crossing point of the electric quantity in the case that the sampling value at the current moment is greater than or equal to 0 and the sampling value at the previous moment is less than 0. I.e. when the zero-point time deviation variation deltat is detected 0 When the time exceeds the set threshold (the time deviation of the sampling positive zero crossing exceeds the difference), the sampling time is adjusted so that the time deviation of the sampling positive zero crossing becomesAmount of conversion DeltaT 0 Greatly reduced (the target can be selected as the variation delta T of the zero time deviation 0 0), namely, rectifying the sampling time so that the sampling forward zero crossing time is consistent with the initial state.
When the second pulse signal is received again, the synchronous signal is considered to be recovered, after the synchronous signal is recovered, the protection device starts timing, when the synchronous signal recovery time exceeds a preset time Tr (30 s can be taken according to field operation experience), the protection device is switched to a protection device data synchronization strategy based on an absolute time scale from the next second pulse to return to the step 2. I.e. the pulse-per-second signal is received again and the time duration Tr is received, the acknowledgement synchronization signal is recovered.
The forward zero crossing time deviation change quantity delta T can be calculated once per cycle 0 Namely, the positive zero-crossing phase angle of the current cycle voltage and the positive zero-crossing phase angle of the last cycle voltage are calculated, and the synchronous reference electric quantity is taken as the A-phase voltage for example, and the time deviation change delta T of the positive zero-crossing point with the cycle number of sq 0 The method comprises the following steps:
wherein,for synchronous reference of electric quantity->The instantaneous sampling value with the cycle number of sq and the sampling sequence number of i (in this example, the A phase voltage is shown); and sq is the synchronous reference electrical quantity +.>The current cycle number of the positive zero crossing, i is the first sampling sequence number after the positive zero crossing;
for synchronous reference of electric quantity->The cycle number of the sampling signal is sq-1, and the sampling sequence number is i;
the frequency voltage Fourier value is the frequency number sq;
as a complex argument function;
the difference between the angle corresponding to the sampling time with the cycle number of sq and the sampling number of i and the angle corresponding to the sampling time with the cycle number of sq-1 and the sampling number of i.
The change amount delta T of the time deviation of the forward zero crossing point can also be calculated once per second 0 Namely, the positive zero-crossing phase angle of the current cycle voltage and the positive zero-crossing phase angle of the last cycle voltage are calculated, and the synchronous reference electric quantity is taken as the A-phase voltage for example, and the time deviation change delta T of the positive zero-crossing point with the cycle number of sq 0 To achieve%Cycle number one second before):
wherein,for synchronous reference of electric quantity->Is the instantaneous sampling value of the cycle number sq and the sampling sequence number i, and sq is the synchronous reference electric quantity +.>The cycle number of the positive zero crossing is i is the first sampling sequence number after the positive zero crossing, and the cycle number before one second of the cycle number sq is +.>；
For synchronous reference of electric quantity->Is>The instantaneous sampling value with the sampling sequence number of i;
the frequency voltage Fourier value is the frequency number sq;
as a complex argument function;
the difference between the angle corresponding to the sampling time with the cycle number of sq and the sampling number of i and the angle corresponding to the sampling time with the cycle number of sq-1 and the sampling number of i.
Variation delta T of time deviation of positive zero crossing point 0 Voltage used in calculationThe normal voltage value is to be determined, and the judgment standard is as follows:
if the electrical quantity is synchronously referencedIf the phase voltage is phase voltage, the three-phase effective value of the phase voltage is rated value, and the phase difference is a normal voltage value when 120 degrees;
if the electrical quantity is synchronously referencedThe effective value of the line voltage is rated value, and the effective value is normal voltage value when the phase difference is 120 degrees.
Whether the voltage is normal or not is judged to be equal to the phase voltage or the line voltage, and whether the three phases are equal in amplitude or not is judged to be 120 degrees in angle difference. Because the invention should use normal voltage, once voltage abnormality occurs, such as system fault short circuit or broken line, or acquisition error caused by voltage loop abnormality, the invention is not applicable any more.
When the voltage of one phase or the voltage of the other phase meets the abrupt change criterion, the protection device does not calculate the forward zero-crossing time deviation change delta T any more 0 And (5) exiting sampling synchronization based on the sampling forward zero crossing time deviation variation.
The mutation quantity criterion is as follows:
wherein,uxfor sampling values of arbitrary phase voltages or line voltages, subscriptsqIndicating the current sample number, subscriptq-1 represents the previous sample number, subscriptq-2 represents the first two sample sequence numbers,ux △set the threshold for voltage step-up is typically determined by the number of weekly wave samples.
In summary, as shown in fig. 3-4, taking the synchronous reference electric quantity as the a-phase voltage as an example, the specific steps of the step 4 include:
(1): when the protection device detects that the sampling value at the current moment is greater than or equal to 0 and the sampling value at the previous moment is less than 0, namely judging that the A-phase voltage is in positive zero crossing, recording the current cycle number j, and sampling the first point after positive zero crossing by the sampling sequence number i, and sampling the first point before positive zero crossingThe sequence number is i-1, i.e. if the A-phase voltage is zero-crossing in the forward direction, the sampling value is recorded asu ai If the AB phase voltage is zero-crossing in the forward direction, the sampling value is recorded asu abi 。
Assuming that the sampling point number of each cycle is N, if i is 1 at the moment, the sampling sequence number of the previous point before the forward zero crossing is N-1, and the cycle number is j-1;
(2): setting the number of sampling points of each cycle as N, sequentially numbering the subsequent sampling points as i+1, i+2 …, N-1 and N-1, and then counting from 0 again, and continuously cycling;
(3): after the cycle sampling is finished, calculating a Fourier value of the voltage, if the A phase voltage is denoted as Ua, and if the A phase voltage is denoted as AB phase voltage, the A phase voltage is denoted as Uab;
and the instantaneous value of the A-phase voltage satisfies the following relation:
the AB phase voltage transient satisfies the following relationship:
the angle corresponding to the sampling time of the current cycle sampling point number i can be calculated according to the sampling value of the current sampling point number i and the previous sampling time by the relational expression；
(4): based onCalculating deviation +.A sampling time point with sampling point number i and sampling time point corresponding to zero crossing point>The method comprises the following steps:
(5): and if the time deviation variable delta T0 ¬ of the sampling forward zero crossing point exceeds a set threshold, adjusting the sampling time, performing data synchronization on two sides of the device, and completing calculation of the electric quantity required by multi-terminal electric protection.
The invention has the beneficial effects that compared with the prior art:
1. when the external clock works normally, the synchronization precision can be ensured to the greatest extent through the synchronization of the absolute time scale and the sampling sequence, and the high-precision synchronization requirement of the multi-terminal electric quantity protection of the power distribution network under the complex wireless communication based on 5G and the like is met.
2. The method comprises the steps of providing a two-stage coding mode of an electric quantity sampling sequence, a forward zero crossing point time deviation variable quantity and a mutation quantity criterion, finishing counting of voltage cycle sampling points and the forward zero crossing point time deviation variable quantity during normal operation, switching to a synchronization method adopting the voltage forward zero crossing points and the cycle sampling sequence when an external clock is abnormal, combining the forward zero crossing point time deviation variable quantity and the mutation quantity criterion to realize multi-terminal electric quantity protection synchronization, and also meeting the synchronization requirement of the multi-terminal electric quantity protection of a power distribution network under the complex wireless communication of 5G and the like.
The present disclosure may be a system, method, and/or computer program product. The computer program product may include a computer readable storage medium having computer readable program instructions embodied thereon for causing a processor to implement aspects of the present disclosure.
The computer readable storage medium may be a tangible device that can hold and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer-readable storage medium would include the following: portable computer disks, hard disks, random Access Memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static Random Access Memory (SRAM), portable compact disk read-only memory (CD-ROM), digital Versatile Disks (DVD), memory sticks, floppy disks, mechanical coding devices, punch cards or in-groove structures such as punch cards or grooves having instructions stored thereon, and any suitable combination of the foregoing. Computer-readable storage media, as used herein, are not to be construed as transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., optical pulses through fiber optic cables), or electrical signals transmitted through wires.
The computer readable program instructions described herein may be downloaded from a computer readable storage medium to a respective computing/processing device or to an external computer or external storage device over a network, such as the internet, a local area network, a wide area network, and/or a wireless network. The network may include copper transmission cables, fiber optic transmissions, wireless transmissions, routers, firewalls, switches, gateway computers and/or edge servers. The network interface card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium in the respective computing/processing device.
Computer program instructions for performing the operations of the present disclosure can be assembly instructions, instruction Set Architecture (ISA) instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, c++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The computer readable program instructions may be executed entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any kind of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or may be connected to an external computer (for example, through the Internet using an Internet service provider). In some embodiments, aspects of the present disclosure are implemented by personalizing electronic circuitry, such as programmable logic circuitry, field Programmable Gate Arrays (FPGAs), or Programmable Logic Arrays (PLAs), with state information of computer readable program instructions, which can execute the computer readable program instructions.
Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: modifications and equivalents may be made to the specific embodiments of the invention without departing from the spirit and scope of the invention, which is intended to be covered by the claims.
Claims (11)
1. A multi-terminal electric quantity protection synchronization method integrating electric quantity and clock information is characterized in that: the method comprises the following steps:
step 1, aiming at multi-terminal electric quantity protection, when external time synchronization is normal, the protection devices on two sides of any one primary device respectively sample according to fixed sampling beats, determine synchronous reference electric quantity, and simultaneously receive second pulses with absolute time marks, which are given by the external time synchronization device;
step 2, the protection devices on two sides of any one primary equipment adjust sampling time according to the received second pulse, electric quantity sampling is carried out when the second pulse reaches the whole second, cyclic frequency and sampling point coding are carried out, cyclic frequency numbers and sampling sequence numbers are obtained, and the data synchronization of the protection devices based on absolute time marks is realized by adopting the cyclic frequency numbers and the sampling sequence numbers;
step 3, when one side protection device does not receive the external second pulse within a set time period, confirming that the external second pulse is in an external time-setting abnormal state from the next cycle, processing according to the time-setting abnormal state, transmitting the time-setting abnormal state to the opposite side protection device, and processing according to the time-setting abnormal state by the opposite side protection device;
and 4, on the basis of the synchronous reference electrical quantity determined in the step 1, sampling synchronization is performed on the basis of the sampling forward zero crossing point time deviation variable quantity by the protection device for time synchronization exception handling, wherein the sampling synchronization is performed on the basis of the sampling forward zero crossing point time deviation variable quantity:
protection device for processing time-lapse abnormality, and method for calculating and sampling forward zero crossing time deviation variation delta T based on synchronous reference electric quantity 0 If the time deviation variation delta T of the positive zero crossing point is sampled 0 If the sampling time exceeds the set threshold, the sampling time is adjusted to make DeltaT 0 The set threshold is not exceeded, wherein the sampling positive zero crossing point refers to the actual zero crossing point of the electric quantity in the case that the sampling value at the current moment is greater than or equal to 0 and the sampling value at the previous moment is less than 0.
2. The multi-port electrical quantity protection synchronization method integrating electrical quantity and clock information according to claim 1, wherein:
in step 1, for multi-terminal electric quantity protection, the protection devices on two sides of any one primary device sample according to a fixed sampling beat and determine synchronous reference electric quantity, which specifically includes:
when external time synchronization is normal, after the protection device is electrified, the protection devices on two sides of any one primary device independently sample according to fixed sampling frequency and sampling interval;
when the protection device detects normal input of any one phase voltage or any two phase voltage, the protection device continuously detects the phase voltage or the line voltage which is preferentially selected by taking the normally input phase voltage or two phase voltage as a priority principle, and sends the result of the phase voltage or two phase line voltage which is preferentially selected at the self side to the opposite side, and the two sides determine the same phase voltage or two phase line voltage as synchronous reference electric quantity to be used for subsequent sampling synchronization based on the time deviation variation of the sampling forward zero crossing point.
3. The multi-port electrical quantity protection synchronization method integrating electrical quantity and clock information according to claim 1, wherein:
in step 2, the protection device a at one side of any one electric power primary equipment samples the electric quantity when the second pulse reaches the whole second of the protection device, records the sampled value acquired at the moment, performs cycle and sampling point coding to obtain cycle numbers and sampling serial numbers, and then sends the acquired sampled value and the cycle numbers and the sampling serial numbers thereof to the opposite side protection device B as sampling data.
4. A multi-port electrical quantity protection synchronization method for integrating electrical quantity and clock information according to claim 3, wherein:
after receiving the sampling data sent by the opposite-side protection device A, the protection device B acquires the corresponding serial number cycle number and sampling serial number of the sampling value in the sampling data, addresses and maps the sampling value in the historical buffer zone data of the side according to the cycle number and the sampling serial number, and finds the sampling value corresponding to the same cycle number and the sampling serial number of the side so as to complete the synchronization of the two-side protection device data based on the absolute time scale.
5. The multi-port electrical quantity protection synchronization method integrating electrical quantity and clock information according to claim 1, wherein:
in the step 3, the set time period is 2 cycles.
6. The multi-port electrical quantity protection synchronization method integrating electrical quantity and clock information according to claim 1, wherein:
in step 4, when the second pulse signal is received again, the synchronization signal is considered to be recovered, after the synchronization signal is recovered, the protection device starts timing, when the synchronization signal recovery time exceeds the preset time Tr, the protection device is switched to the protection device data synchronization strategy based on the absolute time scale from the next second pulse to return to step 2.
7. The multi-port electrical quantity protection synchronization method integrating electrical quantity and clock information according to claim 1, wherein:
calculating the time deviation change delta T of the forward zero crossing point once per cycle 0 The calculation formula is as follows:
wherein,for synchronous reference of electric quantity->The cycle number of the sampling signal is sq, and the sampling sequence number is i; and sq is the synchronous reference electrical quantity +.>The current cycle number of the positive zero crossing, i is the first sampling sequence number after the positive zero crossing;
for synchronous reference of electric quantity->The cycle number of the sampling signal is sq-1, and the sampling sequence number is i;
the frequency voltage Fourier value is the frequency number sq;
as a complex argument function;
the difference between the angle corresponding to the sampling time with the cycle number of sq and the sampling number of i and the angle corresponding to the sampling time with the cycle number of sq-1 and the sampling number of i.
8. The multi-port electrical quantity protection synchronization method integrating electrical quantity and clock information according to claim 1, wherein:
calculating the time deviation change delta T of the forward zero crossing point once per second 0 The calculation formula is as follows:
wherein,for synchronous reference of electric quantity->The cycle number of (1) is sq, the sampling number is i, and sq is synchronous reference electric quantity +.>The cycle number of the positive zero crossing is i is the first sampling sequence number after the positive zero crossing, and the cycle number before one second of the cycle number sq is +.>；
For synchronous reference of electric quantity->Is>The instantaneous sampling value with the sampling sequence number of i;
the frequency voltage Fourier value is the frequency number sq;
as a complex argument function;
the difference between the angle corresponding to the sampling time with the cycle number of sq and the sampling number of i and the angle corresponding to the sampling time with the cycle number of sq-1 and the sampling number of i.
9. The multi-terminal electrical quantity protection synchronization method integrating electrical quantity and clock information according to claim 7 or 8, wherein:
variation delta T of time deviation of positive zero crossing point 0 Employed in calculationsThe judgment standard is that the normal voltage value is as follows:
if the electrical quantity is synchronously referencedIf the phase voltage is phase voltage, the three-phase effective value of the phase voltage is rated value, and the phase difference is a normal voltage value when 120 degrees;
if the electrical quantity is synchronously referencedThe effective value of the line voltage is rated value, and the effective value is normal voltage value when the phase difference is 120 degrees.
10. The multi-port electrical quantity protection synchronization method integrating electrical quantity and clock information according to claim 1, wherein:
in step 4, when the voltage of a certain phase or the voltage of an interphase meets the abrupt change criterion, the protection device does not calculate the forward zero-crossing time deviation change delta T any more 0 And exiting sampling synchronization based on the sampling forward zero crossing time deviation variable quantity, wherein the abrupt change quantity criterion is as follows:
wherein,uxfor sampling values of arbitrary phase voltages or line voltages, subscriptsqIndicating the current sample number, subscriptq-1 represents the previous sample number, subscriptq-2 represents the first two sample sequence numbers,ux △set the threshold is determined for the voltage step-up amount.
11. A multi-terminal electrical quantity protection synchronization system integrating electrical quantity and clock information, using the method of any one of claims 1-10, characterized in that: the system comprises:
the sampling module is used for sampling protection devices on two sides of any one primary equipment respectively according to fixed sampling beats when external time setting is normal aiming at multi-terminal electric quantity protection, determining synchronous reference electric quantity, and receiving second pulses with absolute time marks, which are given by the external time setting device;
the first synchronization module is used for adjusting sampling time by the protection devices at two sides of any one primary device according to the received second pulse, sampling electrical quantity when the second pulse reaches the whole second, and performing cycle and sampling point coding to obtain cycle numbers and sampling sequence numbers, and realizing data synchronization of the protection devices based on absolute time marks by adopting the cycle numbers and the sampling sequence numbers;
the abnormality judging module is used for confirming that the external time-setting abnormality state is in the time-setting abnormality state from the next cycle when the external second pulse is not received by one side protection device within a set time period, transmitting the time-setting abnormality state to the opposite side protection device, and processing the time-setting abnormality by the opposite side protection device;
and the second synchronization module is used for carrying out sampling synchronization on the protection device for processing time synchronization abnormality based on the determined synchronous reference electrical quantity and the sampling forward zero crossing time deviation variation.
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| CN103078401A (en) * | 2012-12-17 | 2013-05-01 | 广东电网公司电力科学研究院 | Time synchronization and sampling synchronization system and method for transformer substation |
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