Participación de cargas flexibles y recursos distribuidos de energía en el control primario de frecuencia de sistemas de potencia con baja inercia
Fecha
2022
Tipo
tesis de maestría
Autores
Incer González, José Manuel
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ISSN de la revista
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Editor
Resumen
Actualmente está en proceso una transición en la configuración de los sistemas eléctricos de potencia. En el esquema tradicional, la generación se concentra en las máquinas sincrónicas cuya operación involucra el uso de grandes masas rotativas que introducen inercia en el sistema, la cual en términos prácticos constituye una reserva de energía instantánea que mejora la estabilidad de frecuencia del sistema. La nueva configuración incluye mayor penetración de generación distribuida con fuentes de energía renovables y conectada a la red mediante interfaces de electrónica de potencia. El valor de la inercia equivalente en estos escenarios es menor y tiene mayor variabilidad temporal y espacial, lo cual se refleja en un aumento en la magnitud de la razón de cambio de la frecuencia ante perturbaciones. Otra vertiente de la transición tecnológica consiste en la expansión de controles inteligentes que habilitan el aprovechamiento de recursos presentes en toda la extensión de las redes para mejorar la estabilidad. Uno de estos recursos son las cargas flexibles, que son aquellas que pueden modificar temporalmente su consumo de potencia sin afectar la funcionalidad de su operación. También está en crecimiento la incorporación de recursos distribuidos de energía hasta los niveles de baja tensión, mediante aplicaciones residenciales como sistemas fotovoltaicos, sistemas de almacenamiento de baterías y vehículos eléctricos. Estos dispositivos son controlados mediante electrónica de potencia lo cual permite activar una
respuesta rápida y modulada ante eventos en la red, por lo que se consideran agentes que irán adquiriendo cada vez mayor relevancia en la operación y estabilidad de los sistemas.
El enfoque del presente proyecto es la implementación de acciones de control a nivel de dispositivo para que poblaciones de cargas flexibles y recursos distribuidos de energía conectadas en el nivel de baja tensión participen en estrategias de control primario de frecuencia, el cual consiste en las acciones automáticas que se presentan en los primeros segundos tras una perturbación que modifica el valor de la frecuencia. Se propone un esquema descentralizado en el cual cada equipo responde a desviaciones medidas localmente. Para evaluar estas estrategias, se realizaron simulaciones que involucran los distintos elementos de las redes hasta los niveles de baja tensión, mediante el uso de una herramienta de desagregación que puebla las redes siguiendo restricciones estadísticas que definen la penetración de los distintos modelos de recursos.
Los resultados obtenidos alcanzan el objetivo propuesto: que la respuesta acumulada de estos dispositivos tenga un impacto apreciable en la respuesta primaria. La respuesta implementada en los dispositivos se activa ante valores tanto de la razón de cambio como de desviaciones de la frecuencia, para que la acción de control
sea más fuerte si se detecta una caída abrupta en la frecuencia como reflejo de una perturbación severa. En este escenario se requiere la contribución de todos los recursos disponibles y los resultados evidencian que las estrategias implementadas contribuyen eficazmente al rescate de la frecuencia para evitar que caiga a valores
límite que pueden activar protecciones que desconecten grandes porciones del sistema con graves implicaciones económicas y un posible colapso del sistema.
A transition in the configuration of electrical power systems is currently in process. In the traditional scheme, generation is concentrated in synchronous machines whose operation involves the use of large rotating masses that introduce inertia into the system, which in practical terms constitutes an instantaneous energy reserve that improves the frequency stability of the system. The new configuration includes greater penetration of distributed generation with renewable energy sources and connected to the grid through power electronics interfaces. The value of the equivalent inertia in these scenarios is lower and has greater temporal and spatial variability, which is reflected in an increase in the magnitude of the rate of change of the frequency in the event of disturbances. Another aspect of the technological transition consists of the expansion of intelligent controls that enable the use of resources present in the entire extension of the networks to improve stability. One of these resources are flexible loads, which are those that can temporarily modify their power consumption without affecting the functionality of their operation. The incorporation of distributed energy resources up to low voltage levels is also growing, through residential applications such as photovoltaic systems, battery storage systems and electric vehicles. These devices are controlled by power electronics, which enables a rapid and modulated response to events in the network to be activated, which is why they are considered agents that will become increasingly important in the operation and stability of the systems. The focus of this project is the implementation of control actions at the device level so that populations of flexible loads and distributed energy resources connected at the low voltage level participate in primary frequency control strategies, which consists of automatic actions that occur in the first seconds after a disturbance that modifies the value of the frequency. A decentralized scheme is proposed in which each team responds to locally measured deviations. In order to evaluate these strategies, simulations involving the different elements of the networks up to the low voltage levels were carried out, through the use of a disaggregation tool that populates the networks following statistical restrictions that define the penetration of the different resource models. The results obtained achieve the proposed objective: that the cumulative response of these devices has an appreciable impact on the primary response. The response implemented in the devices is activated by both the rate of change of frequency and its deviation from nominal values, so that the control action is stronger if an abrupt drop in frequency is detected as a reflection of a severe disturbance. In this scenario, the contribution of all available resources is required and the results show that the implemented strategies contribute effectively to the rescue of the frequency to prevent it from falling to limit values that can activate protections that disconnect large portions of the system with serious economic implications and a possible system collapse.
A transition in the configuration of electrical power systems is currently in process. In the traditional scheme, generation is concentrated in synchronous machines whose operation involves the use of large rotating masses that introduce inertia into the system, which in practical terms constitutes an instantaneous energy reserve that improves the frequency stability of the system. The new configuration includes greater penetration of distributed generation with renewable energy sources and connected to the grid through power electronics interfaces. The value of the equivalent inertia in these scenarios is lower and has greater temporal and spatial variability, which is reflected in an increase in the magnitude of the rate of change of the frequency in the event of disturbances. Another aspect of the technological transition consists of the expansion of intelligent controls that enable the use of resources present in the entire extension of the networks to improve stability. One of these resources are flexible loads, which are those that can temporarily modify their power consumption without affecting the functionality of their operation. The incorporation of distributed energy resources up to low voltage levels is also growing, through residential applications such as photovoltaic systems, battery storage systems and electric vehicles. These devices are controlled by power electronics, which enables a rapid and modulated response to events in the network to be activated, which is why they are considered agents that will become increasingly important in the operation and stability of the systems. The focus of this project is the implementation of control actions at the device level so that populations of flexible loads and distributed energy resources connected at the low voltage level participate in primary frequency control strategies, which consists of automatic actions that occur in the first seconds after a disturbance that modifies the value of the frequency. A decentralized scheme is proposed in which each team responds to locally measured deviations. In order to evaluate these strategies, simulations involving the different elements of the networks up to the low voltage levels were carried out, through the use of a disaggregation tool that populates the networks following statistical restrictions that define the penetration of the different resource models. The results obtained achieve the proposed objective: that the cumulative response of these devices has an appreciable impact on the primary response. The response implemented in the devices is activated by both the rate of change of frequency and its deviation from nominal values, so that the control action is stronger if an abrupt drop in frequency is detected as a reflection of a severe disturbance. In this scenario, the contribution of all available resources is required and the results show that the implemented strategies contribute effectively to the rescue of the frequency to prevent it from falling to limit values that can activate protections that disconnect large portions of the system with serious economic implications and a possible system collapse.
Descripción
Palabras clave
Sistemas de potencia eléctrica, Estabilidad de sistemas de potencia, Estabilidad de frecuencia, Control primario de frecuencia, Cargas flexibles, RECURSOS ENERGÉTICOS