E-STATCOM Power Balancing With Resistive Excess Power Absorption

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Solution Overview

Problem

The limited energy and power capacity of static synchronous compensators (E-STATCOMs) due to fixed energy storage, such as batteries or super-capacitors, hinders effective power balancing in AC power transmission systems, especially with the increasing reliance on renewable energy sources like solar and wind.

Innovation Solution

An arrangement comprising a static synchronous compensator device with a converter unit, energy storage unit, and a power absorption device, controlled by a control device to manage active power exchange, utilizing a resistor unit and current control unit to absorb excess power when the energy storage is full or unable to keep up with demand.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the energy storage capacity of E-STATCOM is increased to improve power balancing capability, then the active power absorption capability is improved, but the physical size and cost increase significantly

Engineering Contradiction:
Improveactive power absorption capabilityVSAvoidphysical size of energy storage
Core Design Contradiction:
PowerVSVolume of stationary object

Solution Approach 1:

The power absorption function is segmented into two independent components: the energy storage unit (batteries/super-capacitors) for storing energy, and the power absorption device (resistive load) for dissipating excess power. This segmentation allows each component to be optimized for its specific function without the need for oversized energy storage capacity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The power absorption device acts as an intermediary component that handles the mismatch between power generation and consumption. Instead of relying solely on energy storage to buffer all power fluctuations, the power absorption device serves as a mediator to dissipate excess power when generation exceeds consumption and storage capacity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the energy storage capacity is increased to handle higher power absorption demand, then the power balancing performance is improved, but the cost increases significantly

Engineering Contradiction:
Improvepower balancing performanceVSAvoidcost of energy storage system
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The system segments the power balancing function into energy storage for temporal energy shifting and power absorption for immediate excess power handling, allowing cost-effective sizing of each component based on specific operational requirements rather than worst-case scenarios.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention merges the E-STATCOM with a power absorption device into a hybrid system that combines the advantages of both technologies: the energy storage capability of batteries/super-capacitors and the unlimited power absorption capability of resistive loads, achieving cost-effective power balancing.

Inventive Principle:
Principle #5Merging (Combining)

3Power

If a larger E-STATCOM is built to increase power absorption capacity, then the active power handling capability is improved, but the physical footprint and installation complexity increase

Engineering Contradiction:
Improvepower absorption capacityVSAvoidphysical footprint
Core Design Contradiction:
PowerVSArea of stationary object

Solution Approach 1:

The system separates the power absorption function from the energy storage function, allowing the power absorption device to be implemented with compact resistive elements that have minimal physical footprint compared to the large volumes required for equivalent energy storage capacity.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enhances power balancing in AC power transmission systems by extending active power absorption beyond the capacity of the energy storage unit, ensuring stable operation even when the energy storage is fully charged or overwhelmed, and providing a backup for the static synchronous compensator.

Implementation Method 1

a power absorption device, wherein the power absorption device comprises a resistor unit

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4664705A1An arrangement and a method for balancing power in an ac power transmission system
Publication Date: 2025.12.17 HITACHI ENERGY LTD
  • EP4664705A1 patent drawingFigure 1
  • EP4664705A1 patent drawingFigure 2
  • EP4664705A1 patent drawingFigure 3

AI summary

An arrangement (1) which is connectable to an alternating current, AC, power transmission system, (2) the arrangement comprising a static synchronous compensator device (3) having a converter unit (4) and an energy storage unit (5) connected with the converter unit; a power absorption device (6); and a control device (9) connected with the static synchronous compensator device and with the power absorption device. The control device is configured to control the static synchronous compensator device to exchange power with the AC power transmission system, and to control the power absorption device in dependence of a charge state of the energy storage unit and a state of the power transmission system. Further, the control device is configured to determine whether or not there is a need to absorb active power from the AC power transmission system in excess of what the static synchronous compensator device is currently absorbing and to, in case of such a need, control the power absorption device to absorb active power.