Power limiting strategies

The Teleport can run various controllers that keep a site within its grid connection limits. This page lists the supported strategies. Make sure that controllable assets and physical grid limit meet the specified requirements.

PV and wind

Using one or more electricity meters for reference data, the Teleport can limit the output of one or more solar and/or wind assets to avoid grid limit violations. Depending on the specific circumstances, different strategies for output limitation can be used. The Teleport supports limitation based on active power, current and apparent power measurements, as well as irradiance data (from a separate sensor) and temperature data.

Most controllers the Teleport offers are closed-loop, after-the-fact controllers using feedback to control assets. These controllers respond to measured changes in output after that change occurs, and may not be suitable for situations where short violations of limits are not allowed. For control on physical limitations, such as circuit breaker or transformer limits, a reservation system can be used instead of an after-the-fact controller. With this controller, a certain maximum power output value is reserved per asset, so the combined power can never exceed the configured limits. This is only available in situations without load or other assets that cannot be controller by the Teleport.

Power limiter

This controller is designed to manage and prevent grid feed-in violations by monitoring active power and dynamically adjusting inverter output. When local load increases, the maximum allowable solar and wind output increases as well. By aggregating data from multiple meters, it ensures that active power limits set by contractual agreements are not exceeded.

This controller can receive setNodeConstraints schedules to temporarily reduce the configured power limit, which can be useful when dealing with Capacity Limiting Contracts (CBC). For more details, see the section on setNodeConstraints.

When to use

Combined solar PV peak and wind power exceeds contractual feed-in limit based on active power (W) and there is local load

When not to use

Combined solar peak PV and wind power exceeds physical limitation (see Current limiter)

Closed-loop control power limiter diagram

Current limiter

This controller prevents physical feed-in or consumption violations from solar inverters and/or wind assets by monitoring phase current measurements. It queries multiple meters at the grid connection and adjusts the active power setpoints if needed to avoid grid violations. The most loaded phase is used for all three-phase calculations to handle phase imbalances.

When to use

Combined solar PV peak and wind power exceeds physical limitation based on current (A) and there is local load

When not to use

Combined solar peak PV and wind power exceeds contractual limitation but does not exceed the physical limitation (see Power Limiter)

Closed-loop control current limiter diagram

Power reservation limiter

This controller reserves specific amounts of power for primary and secondary solar and/or wind assets, prioritizing primary assets to maximize generation while avoiding overshooting power limits. It actively monitors inverter output and adjusts setpoints, ensuring dynamic allocation of available capacity while safeguarding against overshoots in solar and/or wind power generation.

When to use

There is a primary and secondary solar PV and/or wind installation
One installation has preference over the other
The combined capacity of the installations exceeds the physical or contractual grid limitations

When not to use

There is local load

Batteries

Using one or more electricity meters for reference data, the Teleport can limit the output of one or more battery assets to avoid grid limit violations. These controllers work by reducing battery setpoints received through the API based on the available unused capacity on the grid connection. These controllers do not automatically charge or discharge the battery if grid limits are violated. For that, see Peak shaving.

Depending on the specific circumstances, different strategies for setpoint limitation can be used. The Teleport supports limitation based on power and current measurements.

Battery power limiter

This controller safeguards against contractual feed-in or consumption violations using active power measurements. It monitors a single meter at the grid connection to ensure that the battery’s schedule received via the API does not exceed contractual grid limits. If a violation is detected, the controller adjusts the battery’s power output.

When to use

Combined nominal power of the peak local load plus the battery system(s) exceeds the contractual consumption limit
Combined nominal power of the solar PV plus wind plus the battery system(s) exceeds the contractual feed-in limit
Combined nominal power of the battery system(s) alone exceeds the contractual limits

When not to use

Combined nominal power of the peak local load plus the battery system(s) exceeds the physical consumption limit (see Battery current limiter)
Combined nominal power of the solar PV plus wind plus the battery system(s) exceeds the physical feed-in limit (see Battery current limiter)
Combined solar PV peak and wind power alone exceeds the contractual feed-in limit (see Battery peak shaver)
Peak local load alone exceeds the contractual consumption limit (see Battery peak shaver)

Closed-loop control battery power limiter diagram

Battery current limiter

This controller protects against physical feed-in or consumption violations by monitoring phase current measurements. It queries a single meter at the grid connection to assess whether a battery schedule received via the API would breach physical grid limits. If violations are detected, the controller adjusts the battery’s active power setpoint accordingly. The most loaded phase is used for all three-phase calculations to handle phase imbalances.

When to use

Combined nominal power of the peak local load plus the battery system(s) exceeds the physical consumption limit
Combined nominal power of the solar PV plus wind plus the battery system(s) exceeds the physical feed-in limit
Combined nominal power of the battery system(s) alone exceeds the physical limits

When not to use

Combined solar PV peak and wind power alone exceeds the physical feed-in limit (see Battery peak shaver)
Peak local load alone exceeds the physical consumption limit (see Battery peak shaver)

Closed-loop control battery current limiter diagram

Cascade battery power limiter

This two-layer controller manages power limits across multiple grid connections by combining an upper-level cascade controller with lower-level controllers (such as the Battery current limiter or Battery power limiter). The upper controller ensures that the total contractual limits for multiple grid connections are met, while the lower controllers independently manage physical or contractual limits. The system allocates available capacity dynamically across the connections and ensures power limits are not exceeded.

When to use

There are multiple lower-level grid connections that need to be managed by Battery current limiters or Battery power limiters
Those connections are joined on a single upper-level grid connection, where the combined nominal active power ratings of the assets on the lower level cause a risk of violating contractual grid limits

When not to use

The combined nominal active power ratings of the assets on the lower level cause a risk of violating physical grid limits on the upper level

Closed-loop control cascade battery power limiter diagram

EV chargers

Using one or more electricity meters for reference data, the Teleport can limit the output of one or more EV charging stations grouped together to avoid grid limit violations. This controller only limits the power consumption from EV assets, and cannot be combined with PV and battery assets. For that, see Battery peak shaving. The Teleport currently only supports control based on active power limits. See EV distribution logic for a description on how a limit is distributed over a pool of charging stations.

EV power limiter

This controller safeguards against contractual feed-in or consumption violations using active power measurements. It monitors one or more meters at the grid connection to ensure that the active power consumption from the EV assets combined with local load does not exceed contractual consumption limit. If a violation is detected, the controller adjusts the maximum EV power consumption.

When to use

Combined nominal power of the peak local load plus the EV system(s) exceeds the contractual consumption limit
Combined nominal power of the EV system(s) alone exceeds the contractual consumption limit

When not to use

Control must be combined with batteries and/or solar PV and/or wind assets (see Battery peak shaver)

Combining PV, wind and batteries

The Teleport can simultaneously control batteries and solar PV and/or wind assets and, using one or more electricity meters for reference data, limit their output to avoid grid limit violations. If automatic dispatch of the battery system(s) is needed, see Peak shaving. If combining batteries and solar/wind assets on a single grid connection with a risk of exceeding physical limitations such as circuit breakers or transformer limits, see Battery power reservation limiter.

Multi-asset power limiter

This controller can encompass one or more battery systems and one or more PV systems to maintain contractual or physical grid limitations on a single point of measurement. The controller periodically queries a single meter and determines the upper and lower limits for cloud setpoints for all batteries and PV systems connected. Priority is granted to PV generation over battery discharge.

When multiple battery systems are included in the controller, any dispatch power setpoints sent to the batteries will be aggregated into a single setpoint by the Teleport, and divided amongst the battery systems according to their current state of charge. On discharge schedules, the Teleport will favour discharging the battery system with the highest state of charge, and vice versa. When state of charge values are roughly equal, all batteries will receive identical setpoints equal to the total aggregated setpoint divided by the amount of systems. It is currently not possible to retain complete control of the output power of all battery systems when this controller is used.

When to use

Combined solar PV peak and wind power alone exceeds the contractual or physical feed-in limits, and must be curtailed
Combined nominal power of the peak local load plus the battery system(s) exceeds the physical or contractual consumption limits

When not to use

Peak local load alone exceeds the contractual or physical consumption limits and must be peak shaved (see Battery peak shaver)
Peak shaving of excess PV generation is needed (see Battery peak shaver)
No local load (see Battery power reservation limiter)

Battery peak shaver

Similar to the Multi-asset power limiter, this controller can encompass one or more battery systems, zero or more PV systems, up to one EV group to maintain contractual or physical grid limitations on a single point of measurement. The controller periodically queries a single meter and determines the upper and lower limits for cloud setpoints for all batteries, PV and EV systems connected. Priority is granted to PV generation and EV charging over battery.

Additionally, if local load violates the grid consumption limit, the batteries can be configured to supply peak shaving power to correct this violation. Similarly, if power generation causes a violation of the grid feed-in limit, the batteries can be configured to peak shave this additional power. Both of these peak shaving features may be disabled, independently.

The Teleport manages multiple batteries by aggregating power setpoints and distributing them based on state of charge (discharging fuller batteries first, charging emptier ones first). Equal distribution of the aggregated setpoint occurs when charge levels are roughly equal. This strategy limits individual control over each battery’s power output.

The controller can also be configured to adhere to contractual limits on a 15-minute basis, allowing for short violations of the active power (W) limits, so long as the average 15-minute value does not exceed the limit. The controller by default makes a distinction between positive and negative values, so that a violation of the power limit in one direction cannot be resolved by delivering power in the other direction.

State of charge management of the battery systems in this controller can be done in two ways. A state of charge schedule can be configured, which will prompt the system to try to reach a desired state of charge in a given timeframe, optionally at a maximum active power value. Schedules can be configured for every weekday and repeat every week. An example of such a schedule is: try to make sure the battery is charged to 90% between 06:00 and 08:00 on every weekday (Monday-Friday), but use no more than 50 kW active power to do so. Alternatively, a default charge or discharge setpoint can be configured for the battery to follow when no peak shaving is required, and no schedules are active. The battery will only execute this setpoint to the extent allowed by the available capacity on the grid connection. For example, if a 20 kW discharge setpoint is configured but the grid connection only allows 10 kW discharge due to physical or contractual constraints, the battery will be limited accordingly.

Maximum and minimum state of charge (SoC) setpoints can also be defined. The controller will not execute schedules or peak shaving actions that exceed these limits. It is important to note that this feature does not constitute comprehensive SoC management. For instance, it will not prevent battery depletion due to self-discharge.

When combining automatic peak shaving functionality with setpoints (e.g. for power trading purposes), some SoC can be reserved on both ends of the SoC range of the battery. This is done by configuring primary and secondary SoC limits. The secondary (or inner) limits will disallow any setpoints the Teleport received via the cloud that violate these limits, but will still allow peak shaving within the primary (or outer) limits.

When to use

Peak local load alone exceeds the contractual or physical consumption limits and must be peak shaved
Peak shaving of excess PV generation is needed
Peak shaving of excess EV consumption is needed

When not to use

No local load (see Battery power reservation limiter)

Peak shaving for improving self-consumption of energy

This controller is an extension of the Battery peak shaver, and can be used to improve self-consumption of energy behind a meter. The battery is prompted to charge and discharge to correct any violation of the limits set on this controller, but when the battery is not longer able to do correct those violations, feed-in and consumption of power are allowed as normal. Cloud schedules and state of charge schedules (defined above) override the self-consumption optimisation limits.

Self-consumption optimization can be restricted to a certain SoC range, so that for example, a battery would optimize for self-consumption between 30 - 70% SoC and reserve the remainder for peak-shaving based on grid limits. This can be combined with a state of charge schedule to ensure the peak-shaving reserve is automatically restored after it is used.

When to use

The battery must be used to store excess generated energy when it is otherwise exported, and discharge that energy when it would otherwise be imported from the grid

Battery power reservation limiter

This controller reserves a fixed amount of power for each asset (e.g., battery or solar or wind) to prevent overshoots, prioritizing solar and wind output. It monitors inverter output and adjusts setpoints dynamically to ensure that solar/wind generation is maximized while battery discharge capacity is managed. The controller continually balances the power demand between solar/wind and battery to eliminate the risk of power surges.

When to use

The combined capacity of the installations exceeds the physical or contractual grid limitations

When not to use

There is local load

Generators

Generator battery charger

This controller can be used in combination with the Battery peak shaver to allow one or more generators to be turned on with a predefined power output to charge the batteries, allowing them to peak shave local load again. The generators will be turned on when a predefined minimum SoC value is reached on the batteries, and turned off when a predefined maximum SoC value is reached. The battery will not receive an additional setpoint to charge from this controller. A battery with a peak shaving controller is only triggered to charge when a predefined feed-in limit is met. The generator power output must therefore be large enough to reach that peak shaving limit, even when there is substantial local load.

When to use

There are one or more generators available in the system
Peak local load alone exceeds the contractual or physical consumption limits and must be peak shaved
The combined nominal power of the batteries alone is sufficient to peak shave local load, as the generator cannot be used for this purpose directly
The combined nominal power of the batteries is sufficient to avoid exceeding the feed-in limit when the generator is running and the local load stops consuming power

When not to use

There are no generators or batteries available in the system
You need to dynamically reduce the grid limit (setNodeConstraints schedules are not supported by this controller)