CN112653179A - Method for evaluating reliability of weak transmitting end power grid - Google Patents
Method for evaluating reliability of weak transmitting end power grid Download PDFInfo
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- CN112653179A CN112653179A CN201911137402.5A CN201911137402A CN112653179A CN 112653179 A CN112653179 A CN 112653179A CN 201911137402 A CN201911137402 A CN 201911137402A CN 112653179 A CN112653179 A CN 112653179A
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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
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
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- 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
- Y02E10/70—Wind energy
- Y02E10/76—Power conversion electric or electronic aspects
Abstract
The invention belongs to the field of power systems, particularly relates to reliability evaluation of a power system, and particularly relates to reliability evaluation of a transmission-end power grid with large-scale new energy access and direct current transmission. The method is characterized in that a reliability state transition model of a weak transmitting end system is obtained by modeling the reliability of wind power generation, photovoltaic power generation and a direct current system and considering the insufficient voltage supporting capability of a converter station bus caused by direct current access; and calculating the reliability index of the weak sending end system by using a sequential Monte Carlo method and a state enumeration method related to the time sequence. By adopting the calculation method, the problem of reliability evaluation of the existing direct current transmission end power grid with large-scale new energy access is solved, the problem that the traditional reliability calculation method and indexes cannot reflect the characteristics of the direct current transmission end power grid with large-scale new energy access is also avoided, and the calculation result is more comprehensive and accurate compared with the calculation result of a general reliability evaluation index.
Description
Technical Field
The invention belongs to the field of power systems, in particular relates to reliability evaluation of a weak transmitting end system, and discloses reliability evaluation of a power transmission and transmission system with a large amount of new energy access and multi-direct-current transmission.
Background
At present, the existing assessment method aiming at the reliability of the power grid in China comprises a simulation method and an analysis method. The analytical method can calculate the reliability index of the system with high precision, and the simulation method can be applied to reliability analysis of a large system, but still has 3 problems: the existing reliability assessment does not consider a complete set of system for reliability assessment of direct current sending and wind-light combination; secondly, the existing system reliability modeling mainly considers the balance of active power and the evaluation of power utilization reliability, does not consider the influence of voltage, and the weak sending end is mainly caused by the weak voltage supporting capability due to the access of direct current; thirdly, the existing reliability assessment mainly aims at the whole system, and the existing reliability assessment is not individually aimed at the direct current sending.
Disclosure of Invention
Aiming at the problems, the invention provides a method for evaluating the reliability of a weak transmitting end power grid, and evaluation indexes comprise a power supply shortage probability, a power supply shortage expectation and a direct current equivalent outage rate.
The present invention includes the following steps.
1) And constructing a reliability calculation model of the transmission-end power grid with large-scale new energy access.
1-1) establishing a wind power plant reliability calculation model, wherein the wind power plant reliability calculation model comprises a wind speed model, a wind power model and a wind turbine generator shutdown model. The wind power can be obtained according to the wind speed, wherein the wind speed model is simulated by adopting a time-series wind speed model:
Vt＝μt+σtyt
in the formula, mutAnd σtMean wind speed and wind speed variance are respectively represented; y istIt can be obtained from a wind speed time series ARMA (n, m):
the wind turbine generator shutdown model adopts a two-state Markov model and is described by normal operation duration and repair time.
Generally, the normal operation working time obeys exponential distribution, that is, the failure rate λ is a constant, and the duration of the normal operation of the wind turbine generator is as follows:
in the formula, gamma1For evenly distributed random numbers, MTTF is the mean working time, τ1The duration of normal operation.
The repairing time of the wind turbine generator is as follows:
in the formula, gamma2For evenly distributed random numbers, MTTR is the mean repair time, τ2The repair time is.
1-2) building a photovoltaic power generation reliability calculation model
The reliability model of the photovoltaic power generation comprises an illumination model, a power output model and the influence of correction temperature on output power. The construction is similar to that of wind power generation.
1-3) constructing a Direct Current (DC) outgoing reliability state model
Including a bipolar double bridge single 12-pulse connection mode and a bipolar double bridge double 12-pulse connection mode. The bipolar double-bridge single 12 pulse connection mode adopts a 3-capacity state transition mode, and the bipolar double-bridge double 12 pulse connection mode adopts a 5-capacity state transition mode. As shown in fig. 1 and 2.
Since the ac field subsystem affects the reactive power of the converter station, in order to reflect the effect of the voltage on the reliability, a model of the filter of the ac field subsystem, i.e., a reactive capacity table, is established, as shown in fig. 3. And comparing the reactive capacity table to determine whether the direct current can be operated in a derating mode.
The actual transmission capacity of the direct current is determined by combining the reactive capacity table and the state transition diagram of the direct current system, and the determination method is shown in fig. 4: ciRepresenting the available transmission capacity of each element or subsystem in a given enumerated fault state. For example, assume that in some enumerated fault condition, the rectifier side BP2 is derated due to a fault, with a capacity of 0.45, i.e., C1When the positive transmission line fault occurs simultaneously, C is 0.456When the other components are operating normally, the capacity of the enumerated fault state is 0.45 as shown in fig. 4.
2) And determining the reliability index of the system by using a sequential Monte Carlo method.
2-1) the traditional equipment such as the generator, the transmission line and the like only considers that the equipment has two states of operation and outage, the states of all elements are combined to obtain the state of the system, and the state is changed along with time.
2-2) the load model is formed by adding an annual load model provided by data for the system and a standard normal distribution, and the load flow calculation adopts a direct current method.
Obtaining a system reliability index by adopting a sequential Monte Carlo method, wherein the system reliability index comprises the following steps: the power supply shortage probability, the power supply point quantity shortage expectation, the power supply shortage expectation and the direct current equivalent outage rate.
The calculation formula of the direct current equivalent outage rate is as follows:
in the formula
Is in a capacity state CkFrequency of occurrence of
The invention has the beneficial effects that:
(1) compared with the conventional reliability evaluation method, the method for evaluating the reliability of the power grid of the weak transmitting end considers a set of complete reliability evaluation system combining direct current transmission and wind and light, and can describe the power grid of the direct current weak transmitting end in a targeted manner.
(2) A method for evaluating reliability of a weak transmitting end power grid not only considers balance of active power and evaluation of power utilization reliability, but also considers influence of voltage by establishing a capacity model of a filter, and can reflect the characteristic of weak voltage supporting capability caused by direct current access in the weak transmitting end power grid.
(3) A method for evaluating the reliability of a weak transmission end power grid can be used as a basis for guiding a reinforcing scheme of a weak transmission end power grid network frame.
Drawings
FIG. 1 is a diagram of bipolar double-bridge single 12 pulse state transition.
FIG. 2 is a diagram of a bipolar double bridge double 12 pulse state transition.
Fig. 3 is a filter reactive capacity table.
Fig. 4 is a diagram of a method for determining the transmission capacity of the hvdc system.
FIG. 5 is a schematic flow chart of the present invention.
Detailed Description
The following describes the embodiments in detail with reference to an example.
1) Wind power and photovoltaic with different capacities are added to different nodes in the IEEE-RTS-79 system, the double-circuit alternating current lines 36 and 37 between the buses 20 and 23 are replaced by bipolar direct current transmission lines, and therefore the rated transmission capacity of each pole of the bipolar direct current transmission system is set to be 600 MW.
2) According to the method, the total installed capacity is increased to 225MW, meanwhile, the influences of factors in the aspects of detailed wake effect, climate, terrain and the like are considered, an ARMA time series wind speed model is used, the mean value and the variance of the wind speed are set as variables, and the output power of the wind power plant is adjusted so as to evaluate the reliability influence of the wind power plant on the test system under different conditions. After the output power of the wind power plant is determined according to the time sequence, the output power is used as a generator with the output power changing according to the time sequence to be connected to different nodes of the test system, and a plurality of wind power plants can also be connected to the same node or different nodes.
3) Photovoltaic power generation is added to the system as in step 2.
4) The state model of the direct current system is obtained by adopting an FD method, namely the ultrahigh voltage direct current transmission adopts a three-state model, and the ultrahigh voltage direct current transmission adopts a five-state equivalent model. And determining the actual transmission capacity of the direct current system in each state according to the reactive capacity table.
5) And carrying out load flow calculation on each state of the system, simultaneously judging whether the active power of each line exceeds the capacity limit of the active power and whether the system power supply is sufficient, carrying out corresponding load reduction by using an optimal load reduction model, finally comparing the system power supply situation with corresponding data of the load model, and finally forming a required reliability index by statistics after accumulating the power supply situation under each time sequence.
Under the conditions that the average wind speed is 6, the wind speed variance is 1.5, the photovoltaic power generation and the wind power generation are 225MW, and half of each power generation, the power supply unavailability rate of the direct current weak transmitting end system is 0.082, the power supply shortage is expected to be 15.667MW, and the power supply shortage is expected to be 1.33e +5 MWh/y.
Thus, the method provided by the invention is implemented.
It is worth mentioning that the reliability assessment method is not limited to a direct current transmission end power grid containing wind power and photovoltaic, and can be popularized to other new energy power generation systems. Therefore, the above steps are only used for illustrating the technical method of the present invention, and not for limiting the present invention, and any modifications or partial replacements without departing from the spirit and scope of the present invention shall be covered by the claims of the present invention.
Claims (3)
1. A method for evaluating reliability of a weak transmitting end power grid is characterized in that the reliability evaluation index and the index calculation method of the weak transmitting end system composed of large-scale wind-solar power generation and transmitted through high-voltage direct-current transmission can describe the reliability condition of the weak transmitting end power grid in a targeted mode, and the characteristic of weak voltage supporting capability caused by direct current access in the weak transmitting end power grid can be reflected in a mode that the influence of voltage is considered through establishing a capacity model of a filter. The evaluation method can be used as a basis for guiding the strengthening scheme of the grid frame of the weak transmission end.
2. The method according to claim 1, wherein the characteristics of the new energy and the typical weak transmission grid with dc transmission are combined to more fully evaluate the weak transmission grid. The specific evaluation method is as follows:
1) and constructing a reliability calculation model of the transmission-end power grid with large-scale new energy access.
1-1) establishing a wind power plant reliability calculation model, wherein the wind power plant reliability calculation model comprises a wind speed model, a wind power model and a wind turbine generator shutdown model. The wind power can be obtained according to the wind speed, wherein the wind speed model is simulated by adopting a time-series wind speed model:
Vt＝μt+σtyt
in the formula, mutAnd σtMean wind speed and wind speed variance are respectively represented; y istIt can be obtained from a wind speed time series ARMA (n, m):
the wind turbine generator shutdown model adopts a two-state Markov model and is described by normal operation duration and repair time.
Generally, the normal operation working time obeys exponential distribution, that is, the failure rate λ is a constant, and the duration of the normal operation of the wind turbine generator is as follows:
in the formula, gamma1For evenly distributed random numbers, MTTF is the mean working time, τ1The duration of normal operation.
The repairing time of the wind turbine generator is as follows:
in the formula, gamma2For evenly distributed random numbers, MTTR is the mean repair time, τ2The repair time is.
1-2) building a photovoltaic power generation reliability calculation model
The reliability model of the photovoltaic power generation comprises an illumination model, a power output model and the influence of correction temperature on output power. The construction is similar to that of wind power generation.
1-3) constructing a Direct Current (DC) outgoing reliability state model
Including a bipolar double bridge single 12-pulse connection mode and a bipolar double bridge double 12-pulse connection mode. The bipolar double-bridge single 12 pulse connection mode adopts a 3-capacity state transition mode, and the bipolar double-bridge double 12 pulse connection mode adopts a 5-capacity state transition mode.
Because the AC field subsystem influences the reactive power of the converter station, in order to reflect the influence of voltage on the reliability, a model of the filter of the AC field subsystem, namely a reactive capacity meter, is established. And comparing the reactive capacity table to determine whether the direct current can be operated in a derating mode.
2) And establishing the state of each element to form a system state transition diagram. And carrying out load flow calculation on each state of the system, simultaneously judging whether the active power of each line exceeds the capacity limit of the active power and whether the system power supply is sufficient, carrying out corresponding load reduction by using an optimal load reduction model, finally comparing the system power supply situation with corresponding data of the load model, and finally forming a required reliability index by statistics after accumulating the power supply situation under each time sequence.
3. The index for evaluating the reliability of the power grid at the weak transmitting end according to claim 2 is characterized by combining the indexes of the system power generation adequacy, namely the probability of insufficient power supply, the probability of insufficient power supply quantity and the reliability of embodying a direct current transmission system, namely the direct current equivalent outage rate. Therefore, the weak transmission end power grid is evaluated more comprehensively and accurately.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101557106A (en) * | 2009-01-15 | 2009-10-14 | 南方电网技术研究中心 | Method for computing the reliability of UHVDC transmission system |
| CN104682381A (en) * | 2015-01-26 | 2015-06-03 | 南方电网科学研究院有限责任公司 | Method for calculating reliability of flexible direct-current (DC) transmission system of large wind farm |
| CN105224760A (en) * | 2015-10-19 | 2016-01-06 | 重庆大学 | A kind of VSC-HVDC grid-connected system reliability calculation method based on wind energy turbine set |
| CN106253343A (en) * | 2016-09-08 | 2016-12-21 | 国家电网公司 | A kind of grid-connected reliability estimation methods of new forms of energy flexible direct current |
| CN108647415A (en) * | 2018-04-28 | 2018-10-12 | 国网湖南省电力有限公司 | The reliability estimation method of electric system for high proportion wind-electricity integration |
-
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- 2019-11-19 CN CN201911137402.5A patent/CN112653179A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101557106A (en) * | 2009-01-15 | 2009-10-14 | 南方电网技术研究中心 | Method for computing the reliability of UHVDC transmission system |
| CN104682381A (en) * | 2015-01-26 | 2015-06-03 | 南方电网科学研究院有限责任公司 | Method for calculating reliability of flexible direct-current (DC) transmission system of large wind farm |
| CN105224760A (en) * | 2015-10-19 | 2016-01-06 | 重庆大学 | A kind of VSC-HVDC grid-connected system reliability calculation method based on wind energy turbine set |
| CN106253343A (en) * | 2016-09-08 | 2016-12-21 | 国家电网公司 | A kind of grid-connected reliability estimation methods of new forms of energy flexible direct current |
| CN108647415A (en) * | 2018-04-28 | 2018-10-12 | 国网湖南省电力有限公司 | The reliability estimation method of electric system for high proportion wind-electricity integration |
Non-Patent Citations (2)
| Title |
|---|
| TIANSHU ZHANG ET AL: "Reliability Evaluation of Weak Transmission Terminal Power Grid with EHV/UHV Direct Current", 《2019 IEEE INTERNATIONAL CONFERENCE ON ENERGY INTERNET (ICEI)》 * |
| 彭吕斌等: "特高压交流和直流输电系统可靠性与经济性比较", 《电网技术》 * |
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Application publication date: 20210413 |