As power systems transition toward renewable energy, one of the emerging challenges is the reduction of natural damping once provided by synchronous generators. Traditional power systems relied on large rotating machines that inherently damped oscillations. In today’s inverter-based grids, physical inertia and damping are reduced, increasing the risk of low-frequency oscillations, particularly inter-area oscillations that can limit power transfer and, in extreme cases, threaten system security. This makes advanced control strategies like Power Oscillation Damping (POD) more important than ever.
This shift is happening alongside a rapid acceleration of storage deployment. As highlighted in the article Global battery energy storage system (BESS) trends and investment drivers across key regions by Global Segment Lead, Energy Storage, at DNV, Jason Goodhand – BESS is now “at the heart of the global shift toward flexible, renewable-dominated grids,” with solar-plus-storage configurations expected to account for around half of new installations by the mid-2030s. As storage becomes central to grid stability and operation, its role is expanding beyond energy shifting into active system stabilization.
At the same time, the rapid growth of solar generation introduces more variability into the system. Solar’s value is constrained by its daytime-only generation profile, creating periods of surplus and deficit that storage must help balance. But balancing energy is only part of the story, and maintaining stability is equally critical.
What is Power Oscillation Damping (POD) control and how does it work?
Power Oscillation Damping (POD) helps stabilize power transfer by reducing oscillations, lowering additional system costs, and supporting grid operators in meeting regulations that prepare our power networks.
At its core, POD works by counteracting oscillatory disturbances. When oscillations occur, the plant injects power in counterphase to the oscillation, effectively cancelling out part of the disturbance. To do this effectively, the response must be significantly faster than the oscillation itself, typically on the order of ten times faster than the oscillation period.
Because of these demanding response requirements, POD functionality is usually implemented at the inverter level or supported by fast-acting devices such as STATCOMs. PV plants can support POD under suitable operating conditions; their ability to provide consistent damping is influenced by factors such as irradiance variability and available headroom. BESS, thanks to its rapid and precise controllability, is particularly well suited to deliver this function.
POD has become a grid‑code requirement in several countries. Multiple TSOs now explicitly require POD capability for new inverter‑based plants, and others are in the process of adding it to their grid‑code revisions.
Why BESS is well positioned to deliver POD control
Battery Energy Storage Systems bring several advantages to POD applications:
- Fast response times that meet the stringent requirements for oscillation damping
- Bi-directional control, allowing both absorption and injection of power
- High precision, enabling accurate tracking of control signals
- Multi-function capability, combining POD with services like frequency and voltage control
- High resource availability, as long as the SoC is correctly managed
Together, these characteristics make BESS an increasingly valuable asset for transmission system operators working to maintain stability in modern, inverter‑dominated grids.
POD control at GreenPowerMonitor, a DNV company
At GPM, POD control is designed to act effectively against inter-area oscillations while integrating into existing plant architectures.
Unlike conventional inverter-based approaches, GPM’s POD functionality operates through a centralized plant controller, eliminating the need for additional hardware. The system:
- Identifies power-system oscillations and issues corrective setpoints to inverters
- Generates counterphase active and/or reactive power commands to oppose disturbances
- Enhances system stability by increasing the effective damping ratio
The POD solution continuously monitors measurements at the Point of Connection (POC) and can detect oscillations in the frequency range of 0.1 to 2 Hz. Once an oscillation is identified, the controller dynamically adjusts the plant’s power output to mitigate it.
Effective operation depends on very fast response times from both the inverters and measurement systems at the POC, ensuring the control action is timely and impactful.
GPM’s POD functionality is available across the following solutions:
POD in practice
- In use case settings, the ability that the POD Control has to act in counterphase to the disturbance is clearly demonstrated.
- Results show a counter-phase active power response that effectively dampens frequency oscillations.
- This action plays a key role in helping the system maintain stability, which ensures reliable operation when similar disturbances occur in the electrical grid.
GPM’s POD control is able to improve the damping of inter-area disturbances based on the general POD grid code requirements. Moreover, the plant must be capable of set-point tracking at least 10 times faster than the disturbance frequency. Otherwise, the POD control mode could potentially in some cases destabilize the system.
The control technique has been used along with the emulated frequency method to run grid compliance testing and successfully received TSO approval for its operation. The methodology allows the system to showcase its control capability without introducing real disturbances in the grid frequency and voltage.
Conclusion
While POD is increasingly relevant for grid-code compliance, its value goes further. By improving damping and overall system stability, POD can:
- Increase allowable power transfer across networks
- Support more resilient and flexible grid operation
- Reduce curtailment risks allowing operation with fewer constraints
- For developers and operators, this translates into technical and economic benefits.
As renewable penetration grows, storage is becoming a core component of modern energy systems, essential not only for balancing but also for providing the fast, precise stability services that inverter‑dominated grids require. In this landscape, BESS is emerging as a key enabler of advanced functions like POD, helping ensure secure and flexible grid operation as the energy transition accelerates.
Battery Energy Storage Systems and hybrid projects at GPM
To read more about BESS projects and our solutions, download our latest guide ‘How to succeed in BESS projects.’
At GPM, we offer established expertise in grid-code compliance across multiple countries, along with practical experience in POD control and black start, and a strong track record of delivering large, complex projects. We provide the flexibility to integrate with diverse system architectures and meet demanding project requirements, and our solutions comply with key cybersecurity standards. To date, we have delivered BESS storage and hybrid projects across the globe, many of which include advanced technical capabilities such as POD control.
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