Analysis of the Specifics of Selecting Relay Protection and Automatic (RPA) Equipment in Distributed Networks with Auxiliary Low-Power Generating Facilities

Kulikov

2022

J. Phys.: Conf. Ser.

Voltage sags and interruptions in the electric power systems (internal grids) of industrial facilities are caused by various short circuits, including those that occur in external grids. If the depth and duration of such sags and interruptions exceed the rated limits for critical loads, they cause continuous processes to shut down, which produces defective products and entails substantial losses. Russian standards and regulations do not set forth requirements with respect to voltage sags and interruptions, which means that industrial companies cannot sue grid operators for damages. This is why dynamic voltage stability of critical loads involved in continuous processes has to be addressed within the internal grid. They analyze the effectiveness of solutions designed for dynamic voltage stability of critical loads; these can be shared, used on a single site or designed to power secondary circuits. It shows that use of dynamic voltage restorers (DVR) and dynamic voltage sag correctors (DVSC) can be a cost- effective solution if the topology and specifications are configured appropriately. The paper presents general technical requirements for sag and interruption compensators, which are adjusted for cost-effectiveness. Case-specific feasibility testing should be based on daily readings of electrical parameters and electric power quality readings, calculated electromechanical transients, and a feasibility study. Use of DVRs at an industrial facility helped stabilize the voltage curve and reduce the span of irregular voltage fluctuations by a factor of 3, reduce the average voltage at the 6 kV busbars without compromising equipment performance, and improve the starting conditions for AM clusters and self-starting conditions for large AMs. Thus, lowering the elevated voltage at the 6 kV busbars helped cut electricity purchase costs. In most cases where accidents cause disturbances in the external 110 kV grid, DVRs coupled with the automatic voltage controls of power transformers were able to prevent process shutdowns, which constituted the key cost effect.

Section: Overview Of Solutions For Internal Gridsmentioning

confidence: 99%

On ensuring dynamic voltage stability of critical loads in the electric power systems of industrial facilities

Suslov

Kulikov

2022

J. Phys.: Conf. Ser.

“…Empirical data suggests that reduction drives are associated with lower GTE reliability and longer repairs [4],  Phase loads are symmetrized, as synchronous generators are not able to sustain phase-asymmetric loads for long, and relay protection and automation (RPA) systems will disconnect the generator to prevent it from overheating and associated damage. This situation may arise when a DES-equipped area is islanded whilst still carrying a load [5][6][7],  Protections are less likely to initiate DES disconnection due to close SCs or voltage sags to below 0.8Unom for over 0.2 s, which would be critical for conventional GS's,  Input voltage amplitude, phase, and frequency can be controlled with a far shorter delay (≈ 1-3 ms) compared to conventional GS's, which enables the automatic control system (ACS) to run a variety of control algorithms:…”

Section: Benefits Of Inverter Gs'smentioning

confidence: 99%

Inverter generator sets for grids carrying heavy-load users

Симонов²

2020

E3S Web of Conf.

Inverter generator sets (GS) are increasingly common in the electricity industry. The paper dwells upon the core advantages and issues of integrating inverter generator sets that must be considered at the design stage to make informed decisions. The authors present examples of computing the electrical parameters of inverter generator sets in a variety of operating situations. The calculated electromechanical transients show inverter GS’s are more efficient compared to conventional synchronous generators for grid nodes that are ‘weakly connected’ to the grid as well as for islanded operation. The paper further proves that automatic control systems of GS inverters can feasibly feature parameter control laws that conform to the general and additional requirements of the system, which in turn are based on the parameter calculations. It shows that a feasibility study is needed to decide whether to use inverter GS’s.

“…Technical requirements for DERs and their connection to 6-35 kV grids with a capacity of 0.5-1 to 5 MW and those with a capacity of 5 to 25 MW should be drawn up with a similar gradation for photovoltaic, wind, and thermal power plants [13].…”

Section: Development Of Technical Requirements For Dersmentioning

confidence: 99%

Development of technical requirements for generating units of distributed energy resources in the conditions of electric power systems transformation

Filippov

2020

E3S Web of Conf.

The paper describes the prospects for commissioning distributed energy resources (DER) in Russia and considers the historical features, as well as the consequences of structural, qualitative, and quantitative changes in Russia’s UES. The main short and long-term transformational changes, as well as current and future challenges, are described. The main changes in the circuit and operating conditions when integrating DERs into distribution grids in the mass scale are shown. The authors justify the need for making changes in the existing technical requirements for power equipment, relay protection, and automation instruments. Technical requirements for the distributed generation plants and new types of equipment (energy storage systems, devices with power converters, etc.) should be developed. The paper proposes a new approach to the development of the DER-based power distribution schemes considering the specifics of modern generating units and loads. It is noted that solving these issues will ensure reliable DER functioning as part of power systems.