Microgrid Operating Point Control Under Forecast Deviations

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Solution Overview

Problem

Microgrid control systems face challenges in maintaining optimal operating points due to inaccuracies in forecast variables, leading to potential power imbalances and non-optimal operations, as they rely on past and present data without adequate compensation for deviations in forecast values.

Innovation Solution

The method involves modifying operating point values for controllable assets based on asset-specific headroom and total power offsets, using a monotonically increasing function that considers the headroom of each asset and all assets collectively, allowing for adjustments to mitigate power imbalances without additional communication between the Power Management System (PMS) and Energy Management System (EMS).

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If operating point values are determined based on forecast variable values, then the optimal operation of controllable assets is improved, but the reliability of power balance deteriorates when forecast variables are incorrect

Engineering Contradiction:
Improveoptimal operationVSAvoidpower balance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The method pre-calculates compensation values based on forecast variable values before actual deviations occur. When forecast variables are incorrect, these pre-prepared compensation values enable immediate correction of operating point values, maintaining power balance without waiting for deviation detection. This proactive approach resolves the contradiction by preparing corrective actions in advance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The method implements a feedback mechanism where actual values of forecast variables are continuously compared with forecast variable values. When deviations are detected, the system automatically adjusts operating point values using compensation values. This closed-loop feedback ensures reliability is maintained while preserving the benefits of forecast-based optimization.

Inventive Principle:
Principle #23Feedback

2Reliability

If operating point values are adjusted to compensate for forecast deviations, then the robustness of power balance is improved, but the complexity of the control system increases

Engineering Contradiction:
Improvepower balanceVSAvoidcontrol system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The Power Management System performs compensation calculations autonomously using locally available data including forecast variable values, actual values, and asset headroom information. The system self-adjusts operating point values without requiring additional communication with the Energy Management System, making the system self-sufficient and avoiding increased complexity from extra communication infrastructure.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The method adjusts operating point values by changing parameters based on calculated compensation values that consider asset-specific headroom and aggregate headroom. This parameter-based adjustment approach provides a systematic yet relatively simple mechanism to improve robustness without requiring complex control logic or additional system components.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If asset-specific headroom is considered for compensation, then the adaptability of operating point adjustment is improved, but the computational complexity increases

Engineering Contradiction:
Improveoperating point adjustmentVSAvoidcomputational complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The method applies local quality by considering asset-specific headroom for each controllable asset individually when calculating compensation values. Each asset's operating point is adjusted according to its own capabilities and constraints rather than applying a uniform adjustment. This localized approach improves adaptability while keeping computations manageable by focusing on individual asset characteristics.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The PMS selectively adjusts operating point values for assets where compensation is most beneficial, rather than uniformly adjusting all assets. By applying compensation actions partially to specific assets based on their headroom and deviation impact, the system achieves high adaptability without the computational burden of optimizing all assets simultaneously.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3709480B1Method of controlling a microgrid, energy management system, and microgrid
Publication Date: 2024.05.01 HITACHI ENERGY LTD
  • EP3709480B1 patent drawingFigure 1
  • EP3709480B1 patent drawingFigure 2
  • EP3709480B1 patent drawingFigure 3

AI summary

A method of controlling a microgrid (10) comprises retrieving, by an energy management system, EMS (50), a forecast variable value for at least one forecast variable and executing, by the EMS (50), an optimization routine to determine an operating point vector for a plurality of controllable assets (11-14) that is optimal for the retrieved forecast variable value. The method comprises executing, by the EMS (50), the optimization routine to determine several additional operating point vectors for the plurality of controllable assets (11-14), the additional operating point vectors being determined to be optimal for modified forecast variable values that deviate from the retrieved forecast variable value. The method comprises providing both the operating point vector and the several additional operating point vectors to a power management system, PMS (40), of the microgrid (10).