# Control and Limit Enforcements for VSC Multi-Terminal HVDC in Newton Power Flow

## TL;DR

This paper introduces a new method for automatically enforcing controls and limits in VSC multi-terminal HVDC systems within Newton power flow calculations, enhancing stability and efficiency.

## Contribution

It presents a comprehensive VSC MT-HVDC model with integrated control and limit enforcement that maintains computational efficiency during power flow analysis.

## Key findings

- Effective control enforcement demonstrated on IEEE 14-bus system.
- Scalability shown on Polish 9241-bus system.
- No re-factorization needed when limits are reached.

## Abstract

This paper proposes a novel method to automatically enforce controls and limits for Voltage Source Converter (VSC) based multi-terminal HVDC in the Newton power flow iteration process. A general VSC MT-HVDC model with primary PQ or PV control and secondary voltage control is formulated. Both the dependent and independent variables are included in the propose formulation so that the algebraic variables of the VSC MT-HVDC are adjusted simultaneously. The proposed method also maintains the number of equations and the dimension of the Jacobian matrix unchanged so that, when a limit is reached and a control is released, the Jacobian needs no re-factorization. Simulations on the IEEE 14-bus and Polish 9241-bus systems are performed to demonstrate the effectiveness of the method.