Proposed future Ancillary Services in Electric Reliability Council of Texas

Matevosyan, Julija; Sharma, Sandip; Huang, Saijun; Woodfin, D.; Ragsdale, K.; Moorty, Sainath; Wattles, P.; Li, W.

doi:10.1109/ptc.2015.7232743

Cited by 23 publications

(14 citation statements)

References 1 publication

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“…The primary feature of the proposed strategy is that it aims to satisfy the needs of the system during operational timescales, as well as to increase the operational flexibility. That is in conflict with the traditional paradigm, where the current frameworks have been designed based on the capabilities of the installed SGs [9]. The current approach leads to system-specific frameworks, which are not beneficial in the era of smart grid, in which increased penetration of non-synchronous generators and other flexible technologies are considered.…”

Section: Features Of the Proposed Strategymentioning

confidence: 95%

“…It is worth noting that the technical background in this area, according to the literature review, is still in immature stages. Most of the AS frameworks currently adopted are not technology-neutral, and there have only been very recently a few academic efforts to enhance such strategies with modern technologies [7], [8], [9]. However, even in these cases, the proposed strategies are generic without directly dealing with voltage considerations.…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, there is no technical study demonstrating the technical feasibility. Further work described in [9] discusses the shortfalls of the current AS framework of Electric Reliability Council of Texas, and describes the features of a technologyneutral framework to be deployed in the future. However, the focus is also on frequency control issues.…”

Section: Introductionmentioning

confidence: 99%

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Provision of Voltage Ancillary Services Through Enhanced TSO-DSO Interaction and Aggregated Distributed Energy Resources

Rousis

Tzelepis

Pipelzadeh

et al. 2021

IEEE Trans. Sustain. Energy

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The electrical energy generated from renewable energy resources connected to transmission and distribution systems and the displacement of synchronous generators continues to grow. This presages a paradigm-shift away from the traditional provision of ancillary services, essential to ensure a robust system, from transmission-connected synchronous generators towards provision from synchronous and non-synchronous generation (including distribution-connected resources). Given that the available resources at the disposal of system operators are continuously increasing, the flexibility for operating the network can be enlarged. In this context, this paper introduces a dedicated voltage ancillary services strategy for provision of reactive power. A main feature of the proposed strategy is that it is technology-neutral, unlike existing ones that are focused on synchronous generators. The system need for voltage stability is placed at the core of this strategy, which is translated into a requirement for reactive power provision. The proposed strategy achieves, through the combined utilization of distributed generation and traditional resources, to defer the investments in reactive compensating equipment. Dynamic and transient studies are conducted to demonstrate the technical benefits of the strategy, while its practical feasibility is also validated through hardware-in-the-loop testing.

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Section: Features Of the Proposed Strategymentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Provision of Voltage Ancillary Services Through Enhanced TSO-DSO Interaction and Aggregated Distributed Energy Resources

Rousis

Tzelepis

Pipelzadeh

et al. 2021

IEEE Trans. Sustain. Energy

View full text Add to dashboard Cite

show abstract

“…Recent reports and studies have shown frequency stability to be a matter of significant concern due to lack of inertial response from RESs. The independent system operator, Electricity Reliability Council of Texas (ERCOT) has reported a continuous decline in the inertial response of its system and recommends additional inertial response [7,8]. Figure 2 illustrates the change in frequency in the ERCOT interconnection for two time periods for the same amount of generation loss.…”

Section: Introductionmentioning

confidence: 99%

Virtual Inertia: Current Trends and Future Directions

et al. 2017

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Abstract:The modern power system is progressing from a synchronous machine-based system towards an inverter-dominated system, with large-scale penetration of renewable energy sources (RESs) like wind and photovoltaics. RES units today represent a major share of the generation, and the traditional approach of integrating them as grid following units can lead to frequency instability. Many researchers have pointed towards using inverters with virtual inertia control algorithms so that they appear as synchronous generators to the grid, maintaining and enhancing system stability. This paper presents a literature review of the current state-of-the-art of virtual inertia implementation techniques, and explores potential research directions and challenges. The major virtual inertia topologies are compared and classified. Through literature review and simulations of some selected topologies it has been shown that similar inertial response can be achieved by relating the parameters of these topologies through time constants and inertia constants, although the exact frequency dynamics may vary slightly. The suitability of a topology depends on system control architecture and desired level of detail in replication of the dynamics of synchronous generators. A discussion on the challenges and research directions points out several research needs, especially for systems level integration of virtual inertia systems.

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“…Recently, the impact on frequency stability due to a decline in system inertia has become a matter of significant importance as reflected by different reports and studies [3]. The report of electricity reliability council of Texas (ERCOT) [4] discusses the reduction in inertia caused by the economic displacement of synchronous generators in meeting the inertia requirements when wind generation is serving the highest share of load. In the European network of transmission system operators (ENTSO-E) framework, the primary reserve needs to be activated when the frequency deviation exceeds ±10 mHz from the nominal frequency of 50 Hz.…”

Section: Introductionmentioning

confidence: 99%

On Small Signal Frequency Stability under Virtual Inertia and the Role of PLLs

et al. 2018

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This paper presents a methodology that aims at identifying virtual inertia (VI) gain limitations from virtual synchronous generators (VSGs) while maintaining the frequency stability considering the delay associated with the frequency measurement process. The phase-locked loop (PLL) is typically used for frequency estimation that is used to calculate the rate of change of frequency (RoCoF) and it drives the VI loop. The PLL is generally accompanied by a low-pass filter that aims to suppress the impact of harmonics. This filter introduces a delay that when used with the VI control loop causes stability issues for high values of VI gain. A comparison of various PLL approaches suggests that certain variants tend to permit higher value of cut-off frequencies which can be utilized to increase the VI gain limit from VSG. This study presents a method by which the upper limit on VI gain can be quantified and related to the cut-off frequency of the PLL low pass filter that is indirectly representing the delay. It is performed using small signal frequency stability analysis on the frequency domain model of the grid with virtual inertia emulating VSG. The effective maximum VI gain from VSG is explored while satisfying the frequency measurement accuracy specification considering harmonics. The results show that the requirements of reaching a stable operation with sufficient stability margins can still be met with a faster PLL-based system and the potential increases in VI support from VSG can be quantified using the proposed method. The study has been first performed on a single machine single inverter bus (SMSIB) system and is generalized to the multi-machine and multi-inverter system.

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Proposed future Ancillary Services in Electric Reliability Council of Texas

Cited by 23 publications

References 1 publication

Provision of Voltage Ancillary Services Through Enhanced TSO-DSO Interaction and Aggregated Distributed Energy Resources

Provision of Voltage Ancillary Services Through Enhanced TSO-DSO Interaction and Aggregated Distributed Energy Resources

Virtual Inertia: Current Trends and Future Directions

On Small Signal Frequency Stability under Virtual Inertia and the Role of PLLs

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