CN108448618B - Method for detecting island by multi-machine system based on synchronous disturbance curve - Google Patents
Method for detecting island by multi-machine system based on synchronous disturbance curve Download PDFInfo
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- CN108448618B CN108448618B CN201810282964.8A CN201810282964A CN108448618B CN 108448618 B CN108448618 B CN 108448618B CN 201810282964 A CN201810282964 A CN 201810282964A CN 108448618 B CN108448618 B CN 108448618B
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- 230000001360 synchronised effect Effects 0.000 title claims abstract description 28
- 238000000034 method Methods 0.000 title claims abstract description 27
- 238000010248 power generation Methods 0.000 claims abstract description 33
- 238000001514 detection method Methods 0.000 claims abstract description 13
- 230000002159 abnormal effect Effects 0.000 claims description 4
- 230000005611 electricity Effects 0.000 claims description 3
- 238000004140 cleaning Methods 0.000 claims description 2
- 239000000758 substrate Substances 0.000 claims description 2
- 230000007547 defect Effects 0.000 description 1
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Classifications
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- H02J3/383—
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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
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/40—Synchronising a generator for connection to a network or to another generator
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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
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/388—Islanding, i.e. disconnection of local power supply from the network
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
Abstract
The invention discloses a method for detecting an island by a multi-machine system based on a synchronous disturbance curve, which ensures that the curve shape of each disturbance curve is not changed after superposition, the change of the disturbance value is completed by compensation, and the change of a phase is predicted, so that the disturbance characteristic is effectively controlled, the later detection is consistent, the system can still normally work under the asynchronous condition, and the stable and continuous power generation is ensured; by using the scheme, the synchronization requirement is weakened, the disturbance is effectively controlled, and the output curve characteristics except the initial phase can be detected.
Description
Technical Field
The invention relates to the field of power generation systems, in particular to a multi-machine high-performance island-resistant reactive disturbance system
Background
In the high-performance condition detection, the output state is changed by adding disturbance, and the environment change condition can be judged according to the characteristics of a disturbance curve and an output curve. In a single system, the characteristics of the disturbance are easily known, but in a multi-machine system, if the disturbance curve is changed without synchronization, the control of the curve characteristics is lost, and thus the judgment of the change of the environmental condition is lost. The high-performance anti-islanding reactive disturbance also has the problems in a multi-machine power generation system, and the possibility of losing functions is considered.
In a multi-machine high-performance island-resistant reactive power disturbance system in the existing market, whether asynchronization exists needs to be inquired at any time, and communication resynchronization is needed if asynchronization exists. If the plurality of machines are not started simultaneously, the power generation can be carried out only after synchronization by waiting for the start of other machine positions. If the communication is abnormal, the individual communication is interrupted, and the whole system can work normally only by repairing. When the system runs, incomplete synchronization happens, and the system power generation is seriously influenced; the present invention solves such problems.
Disclosure of Invention
In order to solve the defects of the prior art, the invention aims to provide a method for detecting an island by a multi-machine system based on a synchronous disturbance curve; according to the method, the curve shape of each disturbance curve is not changed after superposition, the change of the disturbance value is completed through compensation, the change of the phase is predicted, the disturbance characteristics are effectively controlled, the later detection is consistent, the system can still normally work under the asynchronous condition, and the stable and continuous power generation is ensured.
In order to achieve the above object, the present invention adopts the following technical solutions:
the method for detecting the island by the multi-machine system based on the synchronous disturbance curve comprises the following steps:
injecting disturbance values of each photovoltaic power generation system in a curve form, wherein the curve changes according to a sine curve, and the amplitude compensation of the disturbance values is;
step two, the photovoltaic power generation system reports the working condition to an upper computer after waiting for starting; if the communication is normal, the synchronization of the upper computer is waited; if the communication is abnormal, the power generation is started normally;
step three, synchronizing and normally working to generate power according to the synchronizing signal of the upper computer; the upper computer gives an alarm according to the judgment of (2 lambda-1) × (1 +%) < 1, and the parameter lambda represents: the synchronous power generation proportionality coefficient is set as the number of synchronizations k, PiThe upper computer detects the total power generation amount P for the power generation amount i of the i-th synchronization equal to (1, …, k)General assemblyThen, then
If the disturbance is reduced to be less than 1 time of coefficient, the detection fails due to too small disturbance, and the alarm is that the disturbance is too small;
judging whether the total disturbance value of the upper computer meets the requirement, and judging whether the whole system can work normally;
if the disturbance amplitude calculated by the upper computer is not reduced and meets the condition that (2 lambda-1) × (1 +%). is more than or equal to 1, each lower computer detects the island condition of the machine by the period, frequency, curve shape and amplitude, and the whole system can work normally without detecting the phase;
the characteristics of the disturbance curve include: period or frequency, curve shape, amplitude, phase.
The method for detecting the island by the multi-machine system based on the synchronous disturbance curve,
in the second step, the first step is that,
the specific process of generating the synchronization signal is as follows: upper computer detects total generated energy PGeneral assemblySetting P according to the working condition reported by the lower computeriCalculating the synchronous generating capacity coefficient for the i-th synchronous generating capacity with the number of synchronizations k
Then, a synchronization signal is generated according to (2 λ -1) × (1 +%) < 1.
The method for detecting the island by the multi-machine system based on the synchronous disturbance curve,
in the second step, the first step is that,
the specific process of generating the synchronization signal is as follows: if the difference range of each power generation amount is within v% in the system, and the total number N is set, q is directly calculated as (k/N), and q represents: synchronous scaling factor, k denotes: the number of synchronization has k, then according to
A synchronization signal is generated.
The method for detecting the island by the multi-machine system based on the synchronous disturbance curve,
step four, performing a first step of cleaning the substrate,
the reasoning method for judging whether the disturbance amplitude of the upper computer meets the requirement is as follows:
step a, setting the number N of generated electricity and the number k of synchronization, wherein the disturbance proportion values are consistent
Each generated power is PiIf the disturbance uses an angular frequency omega, the curve shape is sine triangle sin, and the initial phase is thetaiThe synchronized initial phase is 0, the disturbance is output in a curve sine mode, and the disturbance is expressed as d ═ a × sin (ω t + θ); wherein A refers to the disturbance amplitude and also refers to a disturbance value, omega refers to the disturbance angular frequency, and theta refers to the disturbance initial phase;
step b, measuring the size of the disturbance in the system, expressing the disturbance proportion value, wherein the disturbance proportion value is the disturbance value/system output value, and the disturbance proportion value is set as
When the output power generation capacity of the system is P, the disturbance is expressed as
C, if a plurality of systems participate in the work together, the same curve sine disturbance, the same angular frequency omega and the same disturbance proportion value are used for disturbance
Each power generation amountIs PiEach initial phase being θiAnd the total number is N, the total disturbance to the system is expressed as
The overall disturbance value V is obtained by reasoning as follows:
then
Obtaining A sin (ω t) + B sin (ω t + θ)B)＝C*sin(ωt+θC)；
The above formula is considered as a vector addition formula, and A, B and C are vector modes;
obtaining A-B is more than or equal to C and more than or equal to A + B according to the vector;
to obtain
Will Pi*sin(ωt+θi) Viewed as a vector, PiVector modulo according to vector addition formula
To obtain
Obtaining the product according to formula (1) and formula (2);
since the disturbance in the system reduces the disturbance amount, the system fails for detection, so the total amplitude cannot be reduced if guaranteed
If so, the total amplitude can be ensured not to be reduced; by simplifying the formula
And if so, the disturbance amplitude of the upper computer meets the requirement.
The invention has the advantages that: according to the method, the curve shape of each disturbance curve is not changed after superposition, the change of the disturbance value is completed through compensation, the change of the phase is predicted, the disturbance characteristics are effectively controlled, the later detection is consistent, the system can still normally work under the asynchronous condition, and the stable and continuous power generation is ensured.
By using the scheme, the synchronization requirement is weakened, the disturbance is effectively controlled, and the output curve characteristics except the initial phase can be detected.
Detailed Description
The present invention will be described in detail with reference to the following embodiments.
The method for detecting the island by the multi-machine system based on the synchronous disturbance curve comprises the following steps:
injecting disturbance values of each photovoltaic power generation system in a curve form, wherein the curve changes according to a sine curve, and the amplitude compensation of the disturbance values is;
step two, the photovoltaic power generation system reports the working condition to an upper computer after waiting for starting; if the communication is normal, the synchronization of the upper computer is waited; if the communication is abnormal, the power generation is started normally;
as an embodiment, the specific process of generating the synchronization signal is as follows: upper computer detects total generated energy PGeneral assemblySetting P according to the working condition reported by the lower computeriCalculating the synchronous generating capacity coefficient for the i-th synchronous generating capacity with the number of synchronizations k
Then, a synchronization signal is generated according to (2 λ -1) × (1 +%) < 1.
As another embodiment, the specific process of generating the synchronization signal is as follows: the specific process of generating the synchronization signal is as follows: if the difference range of each power generation amount is within v% in the system, and the total number N is set, q is directly calculated as (k/N), and q represents: synchronous scaling factor, k denotes: the number of synchronization has k, then according to
A synchronization signal is generated.
Step three, synchronizing and normally working to generate power according to the synchronizing signal of the upper computer; the upper computer gives an alarm according to the judgment of (2 lambda-1) × (1 +%) < 1, and the parameter lambda represents: the synchronous power generation proportionality coefficient is set as the number of synchronizations k, PiThe upper computer detects the total power generation amount P for the power generation amount i of the i-th synchronization equal to (1, …, k)General assemblyThen, then
If the disturbance is reduced to be less than 1 time of coefficient, the detection fails due to too small disturbance, and the alarm is that the disturbance is too small;
judging whether the total disturbance value of the upper computer meets the requirement, and judging whether the whole system can work normally;
if the disturbance amplitude calculated by the upper computer is not reduced and meets the condition that (2 lambda-1) × (1 +%). is more than or equal to 1, each lower computer detects the island condition of the machine by the period, frequency, curve shape and amplitude, and the whole system can work normally without detecting the phase;
the characteristics of the disturbance curve include: period or frequency, curve shape, amplitude, phase.
The reasoning method for judging whether the disturbance amplitude of the upper computer meets the requirement is as follows:
step a, setting the number N of generated electricity and the number k of synchronization, wherein the disturbance proportion values are consistent
Each generated power is PiIf the disturbance uses an angular frequency omega, the curve shape is sine triangle sin, and the initial phase is thetaiThe synchronized initial phase is 0, the disturbance is output in a curve sine mode, and the disturbance is expressed as d ═ a × sin (ω t + θ); wherein A refers to the disturbance amplitude and also refers to a disturbance value, omega refers to the disturbance angular frequency, and theta refers to the disturbance initial phase;
step b, measuring the size of the disturbance in the system, expressing the disturbance proportion value, wherein the disturbance proportion value is the disturbance value/system output value, and the disturbance proportion value is set as
When the output power generation capacity of the system is P, the disturbance is expressed as
C, if a plurality of systems participate in the work together, the same curve sine disturbance, the same angular frequency omega and the same disturbance proportion value are used for disturbance
Each generated power is PiEach initial phase being θiAnd the total number is N, the total disturbance to the system is expressed as
The overall disturbance value V is obtained by reasoning as follows:
then
Obtaining A sin (ω t) + B sin (ω t + θ)B)＝C*sin(ωt+θC)；
The above formula is considered as a vector addition formula, and A, B and C are vector modes;
obtaining A-B is more than or equal to C and more than or equal to A + B according to the vector;
to obtain
Will Pi*sin(ωt+θi) Viewed as a vector, Pi’Vector modulo according to vector addition formula
To obtain
Obtaining the product according to formula (1) and formula (2);
since the disturbance in the system reduces the disturbance amount, the system fails for detection, so the total amplitude cannot be reduced if guaranteed
If so, the total amplitude can be ensured not to be reduced; by simplifying the formula
And if so, the disturbance amplitude of the upper computer meets the requirement. The specific reasoning process for judging whether the whole system can work normally is as follows:
from the above theory, it is observed that the frequency and the curve shape are not changed after being superimposed, and the output curve shape is not changed. Therefore, the detection can be carried out except the initial phase in the curve characteristic detection.
The single system total disturbance is d ═ a × sin (ω t + θ);
total disturbance of multiple systems is
The two formulas can see that the curve shape is triangular sine, namely the curve shape is not changed;
if the disturbance amplitude is not reduced and the shape is not changed, the output amplitude is not reduced and the shape is not changed; if the phase characteristics are not detected, the whole system cannot be failed;
according to reasoning, the triangle used for multiple systems simultaneously satisfies (2 lambda-1) × (1 +%) > 1, and the whole system can work normally if the output does not detect the phase.
According to the method, the curve shape of each disturbance curve is not changed after superposition, the change of the disturbance value is completed through compensation, the change of the phase is predicted, the disturbance characteristics are effectively controlled, the later detection is consistent, the system can still normally work under the asynchronous condition, and the stable and continuous power generation is ensured.
By using the scheme, the synchronization requirement is weakened, the disturbance is effectively controlled, and the output curve characteristics except the initial phase can be detected.
The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It should be understood by those skilled in the art that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by using equivalent alternatives or equivalent variations fall within the scope of the present invention.
Claims (4)
1. The method for detecting the island by the multi-machine system based on the synchronous disturbance curve is characterized by comprising the following steps:
injecting disturbance values of each photovoltaic power generation system in a curve form, wherein the curve changes according to a sine curve, and the amplitude compensation of the disturbance values is;
step two, the photovoltaic power generation system reports the working condition to an upper computer after waiting for starting; if the communication is normal, the synchronization of the upper computer is waited; if the communication is abnormal, the power generation is started normally;
step three, synchronizing and normally working to generate power according to the synchronizing signal of the upper computer; the upper computer gives an alarm according to the judgment of (2 lambda-1) × (1 +%) < 1, and the parameter lambda represents: the synchronous power generation proportionality coefficient is set as the number of synchronizations k, PiThe upper computer detects the total power generation amount P for the power generation amount i of the i-th synchronization equal to (1, …, k)General assemblyThen, then
If the disturbance is reduced to be less than 1 time of coefficient, the detection fails due to too small disturbance, and the alarm is that the disturbance is too small;
judging whether the total disturbance value of the upper computer meets the requirement, and judging whether the whole system can work normally;
if the disturbance amplitude calculated by the upper computer is not reduced and meets the condition that (2 lambda-1) × (1 +%). is more than or equal to 1, each lower computer detects the island condition of the machine by the period, frequency, curve shape and amplitude, and the whole system can work normally without detecting the phase;
the characteristics of the disturbance curve include: period or frequency, curve shape, amplitude, phase.
2. The method for detecting the islanding based on the multi-machine system with synchronous disturbance curves according to claim 1,
in the second step, the first step is that,
the specific process of generating the synchronization signal is as follows: upper computer detects total generated energy PGeneral assemblySetting P according to the working condition reported by the lower computeriCalculating the synchronous generating capacity coefficient for the i-th synchronous generating capacity with the number of synchronizations k
Then, a synchronization signal is generated according to (2 λ -1) × (1 +%) < 1.
3. The method for detecting the islanding based on the multi-machine system with synchronous disturbance curves according to claim 1,
in the second step, the first step is that,
the specific process of generating the synchronization signal is as follows: if the difference range of each power generation amount is within v% in the system, and the total number N is set, q is directly calculated as (k/N), and q represents: synchronous scaling factor, k denotes: the number of synchronization has k, then according to
A synchronization signal is generated.
4. The method for detecting the islanding based on the multi-machine system with synchronous disturbance curves according to claim 1,
step four, performing a first step of cleaning the substrate,
the reasoning method for judging whether the disturbance amplitude of the upper computer meets the requirement is as follows:
step a, setting the number N of generated electricity and the number k of synchronization, wherein the disturbance proportion values are consistent
Each generated power is PiIf the disturbance uses an angular frequency omega, the curve shape is sine triangle sin, and the initial phase is thetaiThe synchronized initial phase is 0, the disturbance is output in a curve sine mode, and the disturbance is expressed as d ═ a × sin (ω t + θ); wherein A refers to the disturbance amplitude and also refers to a disturbance value, omega refers to the disturbance angular frequency, and theta refers to the disturbance initial phase;
step b, measuring the size of the disturbance in the system, expressing the disturbance proportion value, wherein the disturbance proportion value is the disturbance value/system output value, and the disturbance proportion value is set as
When the output power generation capacity of the system is at home, the disturbance is expressed as
C, if a plurality of systems participate in the work together, the same curve sine disturbance, the same angular frequency omega and the same disturbance proportion value are used for disturbance
Each generated power is PiEach initial phase being θiThe total number is N, then
The total disturbance to the system is expressed as
The overall disturbance value V is obtained by reasoning as follows:
Then
Obtaining A sin (ω t) + B sin (ω t + θ)B)＝C*sin(ωt+θC)；
The above formula is considered as a vector addition formula, and A, B and C are vector modes;
obtaining A-B is more than or equal to C and more than or equal to A + B according to the vector;
to obtain
Will Pi*sin(ωt+θi) Viewed as a vector, Pi′Vector modulo according to vector addition formula
To obtain
According to the formula (1) and the formula (2):
since the disturbance in the system reduces the disturbance amount, the system fails for detection, so the total amplitude cannot be reduced,
if it is guaranteed
If so, the total amplitude can be ensured not to be reduced; by simplifying the formula
And if so, the disturbance amplitude of the upper computer meets the requirement.
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| US9331487B2 (en) * | 2013-03-14 | 2016-05-03 | Rockwell Automation Technologies, Inc. | Method and apparatus for islanding detection for grid tie converters |
| CN106877378A (en) * | 2015-12-13 | 2017-06-20 | 姚秋丽 | A kind of grid-connected photovoltaic system island detection method |
| CN105743122B (en) * | 2016-03-25 | 2018-09-21 | 江苏省电力公司无锡供电公司 | Island detection method suitable for cluster distributed photovoltaic system |
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