Method and device for modeling a long-time-scale photovoltaic output time sequence

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Solution Overview

Problem

Current weather simulation technologies can only predict photovoltaic power generation on an annual or monthly scale, failing to provide a long-time-scale photovoltaic output time sequence necessary for accurate grid connection analysis and planning in power systems.

Innovation Solution

A method using historical data and a Markov chain to simulate weather type transitions and generate a simulated photovoltaic output time sequence, calculating probabilities of transfer between weather types to create a validated time sequence reflecting Probability Density Function, Autocorrelation Function, and short-duration fluctuation characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If existing weather simulation technology is used, then annual/monthly photovoltaic power prediction can be implemented, but long-time-scale power prediction cannot be implemented

Engineering Contradiction:
Improveprediction time scaleVSAvoidprediction capability
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The patent segments the continuous photovoltaic output time sequence into discrete weather type states (clear sky, cloudy, overcast, changing weather). By dividing the prediction problem into discrete states and using Markov chains to model transitions between these states, the system can generate long-time-scale predictions while maintaining reliability through probabilistic modeling of weather patterns.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces weather types as an intermediary between raw weather data and photovoltaic output prediction. The Markov chain models transitions between weather types, which then serve as the basis for generating photovoltaic output sequences. This intermediary layer enables long-time-scale prediction by capturing the probabilistic nature of weather patterns without requiring direct long-term weather forecasting.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If photovoltaic output time sequence is modeled with detailed time resolution, then short-duration fluctuation characteristics can be captured, but data processing complexity increases

Engineering Contradiction:
Improveoutput characteristic representationVSAvoidmodeling complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the photovoltaic output time sequence into discrete time intervals (15-minute resolution) and associates each interval with a weather type state. This segmentation allows the model to capture short-duration fluctuations by tracking weather type transitions at each time step, while the discrete state representation keeps the modeling complexity manageable through the use of transition probability matrices.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the representation parameters by using weather type categories and transition probabilities instead of continuous weather variables. This parameter transformation enables the model to capture complex fluctuation characteristics through a simplified state-space representation, where the complexity is managed through probabilistic parameters rather than detailed physical models.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS10290066B2Method and device for modeling a long-time-scale photovoltaic output time sequence
Publication Date: 2019.05.14 CHINA ELECTRIC POWER RESEARCH INSTITUTE CO LTD
  • US10290066B2 patent drawing
  • US10290066B2 patent drawing
  • US10290066B2 patent drawing

AI summary

A method and device for modeling a long-time-scale photovoltaic output time sequence are provided. The method includes that: historical data of a photovoltaic power station is acquired, and a photovoltaic output with a time length of one year and a time resolution of 15 mins is selected (101); weather types of days corresponding to the photovoltaic output are acquired from a weather station (102), and probabilities of transfer between each type of weather are calculated respectively (103); and a simulated time sequence of the photovoltaic output within a preset time scale is generated (104), and its validity is verified (105). By the method, annual and monthly photovoltaic output simulated time sequences consistent with a random fluctuation rule of a photovoltaic time sequence may be acquired according to different requirements to provide a favorable condition and a data support for analog simulation of time sequence production including massive new energy.