Innovative Energy Management System for MVDC Networks with Black-Start Capabilities

Abstract

Medium voltage DC (MVDC) networks are attracting more attention amid increased renewables penetration. The reliability of these DC systems is critical, especially following grid contingencies to maintain critical loads supply and provide ancillary services, such as black-start. This paper proposes an innovative energy management system (EMS) to maintain reliable MVDC network operation under prolonged AC grid contingencies. Similar EMS designs in literature tend to focus on limited operating modes and fall short of covering comprehensive elongated blackout considerations. The proposed EMS in this paper aims to preserve the distribution network functionality of the impacted MVDC system through maintaining a constant DC bus voltage, maximizing critical load supply duration, and maintaining the MVDC system black-start readiness. These objectives are achieved through controlling generation units between Maximum Power Point Tracking (MPPT) and Voltage Regulation (VR) modes, and implementing a smart load shedding and restoration algorithm based on network parameters feedback, such as storage State of Change (SoC) and available resources. Practical design considerations for MVDC network participation in AC network black start, and the following grid synchronization steps are presented and tested as part of the EMS. The proposed system is validated through simulations and scaled lab setup experimental scenarios.

A Monte Carlo tree search-based method for decision making of generator serial restoration sequence

“…There are two types of generators in the power system, blackstart (BS) generators and non-black-start (NBS) generators (Alassi et al, 2021). BS generators mainly refer to generators with self-starting capability after a large blackout, while NBS generators are generators that require external starting power to start.…”

A Case Study on National Electricity Blackout of Turkey

“…An innovative energy management system (EMS) was proposed for MVDC networks [38]. The system used a power sharing strategy to proportionally distribute power between different renewable energy source units in the voltage regulation mode.…”

“…A parallel restoration strategy based on the A* algorithm was proposed for a power system black start [38]. The proposed strategy managed the start-up of main units with priority in the black-start units, restoration of inter-connection transmission lines, and restoration of important loads.…”

Power Flow Management by Active Nodes: A Case Study in Real Operating Conditions

“…The inclusion of DC sub-networks is becoming attractive in recent years due to the possibility to integrate, at a different power level, RES and energy storage, enabling a meshed hybrid AC/DC distribution grid [15]. The DC sub-networks can be operated in LV [16], MV [17,18] or both [19,20] and can be connected to the AC network via multi-port power electronics converters [21,22]. A hybrid configuration can further improve the flexibility of the entire system in terms of active and reactive power flow controllability [20].…”