The strong development of distributed energy has led to considerable complexity in the operation of microgrids and grids and the need for a fast, safe, efficient, and stable bidirectional operation of all the components of the electrical system, something which has been possible with the incorporation of the IoT (Internet of things) in the processes and management teams of the networks.
In general, a microgrid can be composed of multiple suppliers: photovoltaic, wind farm, hydroelectric plant, generator set, etc., of various storage media: other networks, other batteries, reservoirs, molten salts, supercapacitors, etc. Other consumers: Industrial factories, Commercial, Services, Hospitals, Residential, Etc., and finally elements that can be suppliers, storage, or consumers such as cars, other microgrids and the main grid.
The knowledge and action according to this provision of all these elements corresponds to the control system of the microgrid, EMS (Energy Management System) which together with the BMS (Battery Management System) and the Scada (Supervisory Control and Data Acquisition) constitute the HMI (Human Machine Interface) of the microgrid or network.
The energy flow management and optimization software are the most important part of any microgrid, connected or on island.
In addition to providing energy, the control system ensures that this contribution has the desired quality and may have the function of improving it by achieving a sine wave with the set amplitude and frequency.
Given the imperfections of the generators, the impedance of the lines, the fluctuation of the loads, etc., the waveform of the grid deviates from the sinusoidal shape with which there are variations in voltage, frequency, imbalance between the phases and the generation of harmonics that degrade the quality of the network, leading to damage to consumer systems and equipment, with voltage variations being the most frequent and damaging, so with the correction of voltage and frequency they are the most important factors to be corrected by means of the batteries.
Basically, the control system diagram is:
BMS (Battery Management System)
The control and operation system of the BMS battery oversees controlling the correct operation of the battery for its protection and its relationship with the EMS, EMS and Scada.
Continuously records battery charge level and operation.
It controls the charging and discharging power according to the intensity signal given by a sensor at the battery output and the potential at the output terminals that could have caused a wrong operation.
EMS (Energy Management System)
The EMS includes software and hardware and is the energy control and operation system in charge of measuring and acting for the desired operation of the network: BMS, HMI (Human Machine Interface) and the corresponding SCADA (Supervisory Control And Data Acquisition)
Depending on EMS, PCS, and microgrid or network design, the system can use the battery for the following services:
a) Microgrid frequency control
b) Grid frequency control
c) Voltage control
d) Ramp control
e) Displacement of energy in time
f) Reactive power delivery to the grid
g) Control and management of islands in the network
h) Secondary regulation
j) Auxiliary services (Primary and secondary)
All this passing or without going through zero and being able to control the following elements:
1. Photovoltaic plant
2. Wind Park
3. Hydraulic Turbine
4. Conventional Generation (generator set)
5. Other flow batteries, lithium, lead
8. Fuel Cells
9. Electric car (charging or discharging)
11. Residential, Industrial or Commercial Building
12. Electrical switchgear for installation or testing
13. The control system is expandable so that new units can be incorporated into the network in a very simple and intuitive way.