Research on over Frequency Generator Tripping Configuration Scheme of Regional Grid in Infirm Interconnections and Small Capacity

Abstract

The frequency characteristics of islanding operation are introduced firstly. The magnitude of balance between electromagnetic power and the original motive power and the inertia of the system are the critical factors that affect the frequency. Based on the possible over-frequency problems during the isolated operation of the regional network, the configuration principles of over frequency generator tripping are proposed. Taking an actual grid as an example, an adaptable and efficient configuration solution of over frequency generator tripping is made according to the principles. In addition, the coordination between over frequency generator tripping and over-speed protection controller is studied. This paper brings forward meaningful reference configuration principles for over frequency generator tripping that is suitable to small-capacity regional power grid which is in infirm interconnections.

Mitigation of Over-Frequency through Optimal Allocation of BESS in a Low-Inertia Power System

“…where k is a scalar with a positive value, which controls the predictor step ∆λ 1 . Then, the direction vector ∆z 1 can be measured using Equation (9).…”

“…Using Equations ( 10) and (11), a new initial guess can be achieved. Finally, by using predictor step and initial guess, an actual point in the system profile can be computed by solving Equations ( 12) and (13).…”

“…Following the loss of an interconnection in a low-inertia grid under power export conditions, network frequency can go above a certain threshold [8]. As a result, over-frequency relays disconnect the online generators [9]. Consequently, cascading tripping of generators may take place, which eventually can cause a significant amount of generation loss.…”

“…An over-frequency mitigation scheme via the tripping of generators located close to the disturbance is suggested in [10]. Furthermore, an Over-Frequency Generator Shedding (OFGS) technique is proposed in [11], where coordination is preserved between the over-speed protection controller and generator shedding relays. Furthermore, an active power reduction scheme of virtual power plants aided by a decision tree strategy is reported in [12].…”