Decoupled Multi-Port Impedance Modelling Method of Transmission Network in Inverter-Fed Power Plant

Abstract

This paper presents a decoupled multi-port impedance modelling method of transmission network for stability analysis of inverter-fed power plant. The decoupled three-port and four-port impedance model are first derived. On the basis of them, multi-port impedance model of transmission network are deduced, where multiple branches-based transmission network is modelled by means of Norton equivalent circuit. In addition, stability analysis based on proposed impedance network modelling method is performed. Simulation results are given to validate effectiveness of the proposed decoupled multi-port impedance modelling and stability analysis method. The proposed modelling method is able to simplify impedance modelling procedure, which performs impedance based stability analysis for inverterfed power plant with complicated transmission network in a computation-less way. Index Terms-Decoupled impedance modelling, inverter-fed power plant, impedance-based stability analysis, transmission network.

Effect of Reactive Power Characteristic of Offshore Wind Power Plant on Low-Frequency Stability

“…Impedancebased stability criterion (IBSC) for three-phase GCI has been proposed to investigate these oscillation phenomena, where impacts of the control loops on terminal impedance have been investigated by various impedance models [3]- [7], [9]- [14]. The mechanism of high-frequency instability phenomena induced by the interaction between inner current control loop and transmission cable is investigated in [6], [10], [11]. The analysis results indicate that the impedance formula of a GCI with only consideration of inner current control loop does not consist of active power reference.…”

DQ impedance‐decoupled network model‐based stability analysis of offshore wind power plant under weak grid conditions

“…dc‐link voltage control loop and power control loop [7–11]. In addition, improper design of inner current control loop may lead to high‐frequency instability phenomena under weak grid conditions [12, 13]. For simplicity, only PLL and inner current control loop, as representatives, will be investigated in this paper.…”

“…Many works have been reported to avoid RHP poles calculation for stability assessment of large‐scale power electronic‐based AC power systems [4, 21–32]. In [21], the theoretically‐derived dq impedance models of the GCIs and transmission lines are connected based on system topology, based on which a loop impedance model is derived.…”

“…On the other hand, the Nyquist stability criterion is performed sequentially from the farthest bus to point of common coupling (PCC) in [21, 30–32], where RHP poles calculation is avoided. In each step, ratio of the nearest component impedance which is at the right side of a bus and total impedance which is at the left side of the bus is calculated, based on which the encirclement number around of Nyquist plot of the impedance ratio is counted.…”

Impedance-Based Modelling Method for Length-Scalable Long Transmission Cable for Stability Analysis of Grid-Connected Inverter

“…Impedance-based stability analysis method has been widely proposed to perform stability assessment of power electronicsdominated power plant [5]- [8], where stability is predicted by analyzing whether the ratio of grid impedance and GCI output impedance satisfies the Nyquist stability criterion or not [5]. Existing works have established impedance models of three phase GCIs in dq domain [9], phase domain [10] and sequence domain [11].…”