Tools to monitor PV hybrid system performance – pv magazine International

Could 11, 2023 IEA-PVPS

A hybrid power system is a mixture of two or extra power sources working collectively to provide electrical energy. Within the case of PV hybrid programs, photo voltaic power is mixed with a number of power sources, equivalent to diesel turbines, batteries, or wind generators. The primary aims of PV hybrid programs are to extend the reliability and effectivity of electrical energy manufacturing, scale back power prices and scale back the environmental impression of power manufacturing.

To evaluate whether or not PV hybrid programs obtain these targets, system information have to be monitored and analyzed. Information units are sometimes giant and sophisticated however could be analyzed inside a short while with the assistance of acceptable visualization instruments. An IEA-PVPS Activity 18 report describes easy-to-use, standardized information visualization for PV hybrid programs.

The tactic permits a fast overview of the efficiency of the programs to measure the success or shortcomings of the optimization regime or to check the efficiency of various programs in a fleet. This standardization and the potential of evaluating programs permits for the identification of weak factors within the technique of working and managing a system. This enables operators to enhance the effectivity of the programs.

The info visualization focuses on battery information as a result of it’s the costliest part of any PV hybrid system. To optimize the usage of the battery and to extend the lifetime of the battery is all the time the important thing to cut back the entire price of operation of PV hybrid programs. To hold out the proposed information visualization, it’s needed to observe numerous battery parameters equivalent to voltage, present and temperature. The visualization attracts temperature warmth maps, temperature profiles and day by day power profiles, in addition to different combinatorial metric visualizations, that are needed to investigate the load and the enter sources.

With the assistance of those numbers, it’s potential to regulate and adapt a number of charging and discharging set-points, scheduled generator begin and cease factors or every other utilized administration technique. in the true life operation of the precise system. That is typically extra priceless than pre-planned methods as a result of in lots of programs the precise utilization could be very completely different from the deliberate and scheduled operation.

This text will concentrate on some particular visualizations for PV hybrid programs to show their utility. Extra data could be discovered within the report, which fits by way of completely different regimes of monitoring and visualization for various kinds of programs together with pico photo voltaic, traditional photo voltaic house programs (50 W to 500 W), inverter-based programs (500 W to five kW), PV hybrid programs (5 kW to 250 kW) and bigger microgrid programs (over 250 kW).

For instance, to investigate the working technique of the power administration system, it’s cheap to think about the habits of the battery present and state of cost (SOC) relying on the battery voltage. To do that, a diagram could be created as proven under. The x-axis represents the conventional battery voltage, whereas the battery present or SOC is positioned on the y-axis. Displaying all information units leads to a dot-cloud.

The voltage is displayed as regular battery voltage at [V/cell] and represents the x-axis of the 2 dot-cloud diagrams above. The present is normalized to the battery capability [A/Ah] and reveals the y-axis within the left diagram. Within the case of a 100Ah battery the score implies that a present of 10A is proven as 10A / 100Ah = 0.1A / Ah within the given instance. 5A/100Ah = 0.05A/Ah. Optimistic values ​​are charging currents whereas detrimental values ​​are discharging currents.

Within the case of the given instance on the left aspect of the determine (purple dots) it seems:

• Absolutely the values ​​of the utmost cost and discharge currents are the identical. This reveals an inexpensive measurement of the system as a result of the used turbines together with PV can recharge in nearly the identical time during which they’re discharged.
• The utmost charging and discharging currents are discovered at very low and really excessive voltages. Within the given instance, currents that cost and discharge the battery inside a brief time frame happen regularly.

Within the case of the given instance on the precise aspect of the determine (blue dots) it seems:

• The SOC distribution is comparatively evenly weighted in a cloud inside the excessive voltage and SOC window. Typical battery hysteresis could be seen as vertical peaks within the blue dotted cloud. In comparison with a great SOC battery situation the realm between the 2 “traces” is kind of vast giving details about the accuracy of the system SOC calculation. On this case the efficiency is low.
• It may also be seen that always low battery voltage is seen together with a really excessive SOC score. This means that top water movement is obvious within the system. Which means that the chosen battery capability is small in comparison with the utilized inverters and leads to a brief battery autonomy time.
• Any such diagram additionally permits understanding the remaining capability of the battery and its age. When a great SOC algorithm is used, the width of the SOC window is small. Throughout the battery growing old course of the SOC window will widen considerably. Additionally, the density of dots with excessive SOC score and low battery voltage will increase. On the identical time the variety of dots with low SOC values ​​​​and excessive battery voltages will increase.

For an skilled system designer or operator, the insights gained from the above information visualizations are clear and significant. A system that performs as anticipated will produce information visualizations that “look” nominal whereas programs that carry out poorly, or programs which can be improperly designed seem non-nominal.

Having visualizations that may present instant suggestions to venture stakeholders will help optimize the system and make modifications for future designs. IEA-PVPS Activity 18 hopes that its report on PV hybrid system information visualizations will assist system operators to optimize their programs.

This text is a part of the IEA PVPS program’s month-to-month column. It’s contributed to the IEA-PVPS Activity 18 – Off-Grid and Edge-of-Grid PV Techniques. Extra data could be discovered within the latest report on Activity 18: PV-Hybrid System Information Visualization Suggestions.

By Christopher Martell, GSES, Australia