جستجوی مقالات مرتبط با کلیدواژه « frequency stability » در نشریات گروه « فنی و مهندسی »

Using security-constrained unit commitment as a preventative method of supplying power system frequency response can increase the penetration of renewable energy sources while maintaining frequency response parameters within their allowable range. Moreover, it can reduce the need for corrective actions such as under-frequency load shedding and can prevent power blackouts. So far, there have been two views about the virtual inertia of grid-connected energy storage units, pessimistic (lack of virtual inertia) and optimistic (failure-free frequency response). However, in reality, the frequency response supply system may experience malfunction and incorrect operation, which is modeled and analyzed in this paper from a techno-economic standpoint. False sensor detection, control system malfunction, wrong power injection of energy storage, inverter failure, improper parameter setting, etc., can all be considered disruptive factors. However, in order to have a more general model, the article avoids dealing with the reason behind the poor performance of the storage system and focuses only on its effects, i.e., the possibility of the storage system not participating correctly. The proposed model takes into account the system's frequency stability by linearly integrating the nadir frequency and the rate of change of frequency limits to the robust mixed-integer linear programming model with YALMIP and MOSEK solvers. The results of implementing this model in the IEEE-RTS96 network show that neglecting energy storage system malfunctions can lead to violations of frequency constraints that must be compensated by increasing costs and keeping more online units with more free headroom.

Frequency is one of the important components of the power system, which must be within the allowable range. With the occurrence of a severe disturbance, the governor system and rotating storage of power plants do not have the necessary ability to prevent a rapid drop in frequency. Under frequency load, shedding plans are one of the most important protection plans that are responsible for keeping the frequency within the permissible range in the event of severe disturbances. In this paper, while accurately calculating the active power required to keep the frequency constant, by affecting the spinning reverse energy of power systems in the load shedding stages, the minimum load is calculated to recover the frequency of the power system and the load is cut off. Designed for 4 stages of load shedding operations, in each stage, the amount of power deficit compensated by the rotating storage energy is checked and then the load is cut off. As an example, for a disturbance of 0.8 per unit, the amount of 0.3 per unit is compensated by the stored energy and only 0.5 per unit of load is disconnected from the network. In order to show the effectiveness of the proposed plan, the simulation results of using this plan for an island system have been compared with the simulation results of two common offloading plans. The results show that the proposed design shows more reliable and appropriate performance than the other two common designs. In this paper, while accurately calculating the active power required to keep the frequency constant, by affecting the spinning reverse energy of power systems in the load shedding stages, the minimum load is calculated to recover the frequency of the power system and the load is cut off. Designed for 4 stages of load shedding operations, in each stage, the amount of power deficit compensated by the rotating storage energy is checked and then the load is cut off. As an example, for a disturbance of 0.8 per unit, the amount of 0.3 per unit is compensated by the stored energy and only 0.5 per unit of load is disconnected from the network. In order to show the effectiveness of the proposed plan, the simulation results of using this plan for an island system have been compared with the simulation results of two common offloading plans. The results show that the proposed design is more reliable and appropriate performance than the other two common designs.

In this paper, the effect high penetration of renewable energy resources on the transmission network stability is investigated. By increasing the number of inverter-based resources, the overall inertia of the network decreases and the stability of the network is affected. In order to analyze the behavior of low-inertia grids, initially according to the type of traditional power plants and wind turbines, appropriate dynamic modeling has been done. Then, by creating a short circuit, the effect of increasing the penetration of wind turbines on the voltage and frequency stability is evaluated. The effect of duration and location of the fault on network stability has also been investigated. The study network is a modified Kundur’s four-machine system modeled in PowerFactory.

This paper proposes a new voltage stability assessment method based on vector analysis method. This index extraction process relies on measurements of active and reactive powers from connected buses to the generator buses. Therefore, a limit for beginning of voltage collapse is determined based on the maximum power transfer theory. On the other hand, when the system requires load shedding, a new voltage-frequency load shedding has been employed. This load shedding makes voltage and frequency stabilities be guaranteed via clustering of all loads as allowable and unallowable, and prioritizing allowable cases. Simulation results in DIGSILENT Power Factory software on IEEE-39 bus dynamic test system demonstrate the efficiency of proposed approach with respect to other methods.