Bipole HVDC Commissioning Control for Neutral Current Limits

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Solution Overview

Problem

During the commissioning of bipole power transmission networks, the electrical current flowing through the neutral arrangement can exceed its rating, potentially damaging components and causing the HVDC scheme to trip.

Innovation Solution

A computer-implemented method of controlling a bipole power transmission network by configuring power converters to regulate DC voltages and AC voltage outputs, synchronizing converters, and controlling them to regulate AC and DC power based on measured and reference electrical currents, ensuring the current through the neutral arrangement does not exceed its rating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If round-power mode is used for commissioning, then the HVDC network can be tested before offshore windfarm commissioning, but the electrical current through the neutral arrangement exceeds its rating

Engineering Contradiction:

Improvecommissioning capabilityVSAvoidneutral arrangement current overload

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The control system dynamically adjusts operating parameters (power flow distribution between poles, converter station outputs) to maintain neutral arrangement current within rated limits while enabling round-power commissioning mode

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The control system continuously monitors the neutral arrangement current and uses this feedback to adjust power converter outputs, ensuring current remains below the rating threshold during commissioning operations

Inventive Principle:

Principle #23Feedback

2Power

If electrical current flows through both electrical poles in the same direction, then power can be transmitted efficiently, but the returning current exceeds the neutral arrangement rating

Engineering Contradiction:

Improvepower transmission efficiencyVSAvoidneutral arrangement current capacity

Core Design Contradiction:

PowerVSStrength

Solution Approach 1:

The system adjusts power flow parameters and converter station operating points to distribute current in a way that maintains transmission efficiency while limiting neutral arrangement current to safe levels

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The control system dynamically balances power flow between the two electrical poles based on real-time conditions, adjusting the distribution to prevent neutral arrangement overload while maintaining efficient power transmission

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS20250175002A1Commissioning of bipole power transmission networks

Publication Date: 2025.05.29 GE INFRASTRUCTURE TECH LLC

AI summary

A computer-implemented method of controlling a bipole power transmission network including first, second, third and fourth power converters, a first electrical pole, a second electrical pole, and a neutral arrangement. The method including: configuring the first and second power converters to regulate first and second DC voltages of the first and second electrical poles; configuring the third and/or fourth power converter to control an AC voltage output from the third or fourth AC sides; configuring the third and/or fourth power converter to be synchronised to the AC voltage; and controlling the third and/or fourth power converter to regulate an AC power at the third or fourth AC side and/or to regulate a DC power at the third or fourth DC side, as function of: a measured value of a first electrical current flowing through the neutral arrangement; and a reference value for the first electrical current.