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Teleport

Control strategies

The Teleport can act as a local EMS and execute a variety of active control strategies. Among them, Teleport supports:

Regarding physical grid limitations

Safeguarding grid limits and peak shaving

Static power limitation

Each solar and wind asset connected to Teleport can have static production limits configured. This ensures that an asset does not receive a setpoint above or below the configured limits. Each asset can have:

  • Upper Limit - Defines a static upper limit on curtailment of an asset. This configuration is useful for locations with limited grid capacity with negligible local consumption. The default upper limit is 100%.
  • Lower Limit - Defines a lower limit on curtailment of an asset. This configuration is useful for assets that should not be curtailed to 0% or for locations with a constant base load where part of the generated energy can always be self-consumed locally. The default lower limit is 0%.

Curtailment setpoints through the API can be scaled with respect to the defined limits. The scaling functionality, if enabled, normalizes the setpoint between the defined limit. The impact of the scaling factor on the curtailment setpoint sent to the asset can be seen in the visualization below.

Scaling factor visualization Impact of scaling factor on curtailment setpoint

Dynamic limitation of solar PV

Using one or more electricity meters for reference data, the Teleport can limit the output of one or more solar 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 control strategies 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 control strategy, 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. In contrast to Static production limits, when local load increases, the maximum allowable solar 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 limitPower 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 limitPower.

When to use

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

When not to use

Closed-loop control power limiter diagram Closed-loop control power limiter diagram

Current limiter

This controller prevents physical feed-in or consumption violations from solar inverters 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. Note that the limit configured in the controller will be lower than the actual limit (see here).

This controller can receive limitPower 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 limitPower.

When to use

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

When not to use

Closed-loop control current limiter diagram Closed-loop control current limiter diagram

Apparent power limiter

This controller prevents solar inverters from exceeding contractual feed-in limits based on apparent power (VA). If there is a risk of tripping the grid connection due to current overshoot, refer to the Current Limiter. The controller queries a configurable number of grid connection meters at regular intervals and imposes an upper limit on the inverter’s apparent power. The inverter or plant controller adjusts the active power setpoint as needed, always prioritizing reactive power delivery.

When to use

  • Combined solar PV peak power exceeds contractual feed-in limit based on apparent power (VA) and there is local load

When not to use

Closed-loop control apparent power limiter diagram Closed-loop control power limiter diagram

Temperature power limiter

Designed to curtail solar inverter output based on transformer temperature readings, this controller activates when a specified temperature threshold is reached. It implements hysteresis to prevent frequent switching of the curtailment and ensures stable control by adjusting inverter setpoints as the transformer temperature fluctuates.

When to use

  • The temperature of a transformer is largely dependent on the PV output power, and this transformer temperature must be managed actively

When not to use

  • There is no temperature sensor available at the transformer

Power reservation limiter

This controller reserves specific amounts of power for primary and secondary solar 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 power generation.

When to use

  • There is a primary and secondary solar PV 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

Dynamic limitation of battery setpoints

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 control strategies 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.

This controller can receive limitPower 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 limitPower.

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 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 the battery system(s) exceeds the physical feed-in limit (see Battery current limiter)
  • Combined solar PV peak 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 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. Note that the limit configured in the controller will be lower than the actual limit (see here).

This controller can receive limitPower 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 limitPower.

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 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

Closed-loop control battery current limiter diagram 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.

This controller can receive limitPower 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 limitPower.

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 Closed-loop control cascade battery power limiter diagram

Combining solar PV and batteries

The Teleport can simultaneously control batteries and solar PV 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 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. Note that the limit configured in the controller will be lower than the actual limit (see here).

This controller can receive limitPower 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 limitPower.

When to use

  • Combined solar PV peak 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

Battery peak shaver

Similar to the Multi-asset power limiter, this controller can encompass one or more battery systems and zero 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.

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. Note that the limit configured in the controller will be lower than the actual limit (see here).

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.

This controller can receive limitPower 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 limitPower.

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

When not to use

Battery power reservation limiter

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

Balancing and congestion services

Zonbalans (Enexis)

The Zonbalans power limiter dynamically reduces feed-in capacity based on irradiance levels using a predefined droop curve, based on the Enexis Zonbalans program. It ensures that feed-in limits are maintained by reducing power proportionally to solar irradiance. The controller works with a single Power limiter.

This controller can receive limitPower 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 limitPower.

When to use

  • Participating in the Zonbalans program from Enexis

When not to use

  • There is no irradiance sensor or pyranometer available

Solar irradiance power limiter (aFRR)

This controller limits the power production of solar installations based on irradiance measurements. It reduces output power to match grid requirements by calculating uncurtailed power using weather data, specifically irradiance levels. This setup is ideal for facilities providing automatic Frequency Restoration Reserve (aFRR) services for solar assets. For more information about how to use this type of power limitation, see our API documentation.

When to use

  • The solar PV output power must be limited relative to the theoretical uncurtailed power, such as for aFRR services

When not to use

  • There is no irradiance sensor or pyranometer available

Capacity Limiting Contracts (CBC) and GOPACS

Our API supports the control command for managing configured feed-in and consumption limits of grid power controllers. Specifically, refer to the limitPower command detailed in our API documentation, under limitPower. This command is instrumental in managing emerging services like Capacity Limiting Contracts (CBC), allowing for dynamic adjustment of feed-in and consumption limits for active controllers running on the Teleport.

It allows for temporarily reduduction/setting of the feed-in/consumption limits and is relevant for Peak shaving consumption using batteries and Power limiter controllers.

It is possible to schedule limitPower command together with other scheduling commands (such as setBatteryOperation or limitProductionPower). The grid power control will periodically evaluate the local conditions (considering currently active feed-in/consumption limits) and will restrict the operation of the assets within a safe limit. The image below shows how the limitPower and limitProductionPower commands can be used concurrently to adhere to CBC limits and curtail assets simultaneously. In curtailment period 1 at 9:30, the limitProductionPower command is used to curtail the solar asset to 0%. This does not impact the grid limitation of 1 MW. At 12.00, limitPower is used to limit total grid feed-in to 0.5MW, which causes reduced production of the solar asset. In curtailment period 2, at 14:00, the limitProductionPower command is used to once again curtail the asset to 0% while limitPower limits the grid feed-in to 0.5MW. The lowest of these two limits is adhered, and production goes to 0W.

Combining limitPower and limitProductionPower commands Combining limitPower and limitProductionPower commands

Active controllers that support limitPower schedules:

Real-time interface

Allows the Teleport to function as an RTI Customer Endpoint. See our Real-time interface page for more details.

Other control strategies

Modbus server

The Teleport can be configured to have a local Modbus TCP server running. See our Modbus TCP page for more details.