Low Cost Phasor Measurement Unit    

Grid sensor and measurement units    

Low cost phasor measurement units are advanced measurement devices that increase grid observability with a very high time-resolution thanks to high reporting frequency and with high accuracy. Moreover, these are low-cost devices, while their design of hardware and software is fully open source and designed in a flexible way so that further features and applications can be relatively easily integrated.

Target group

The low-cost PMU could be deployed by TSOss and by DSOs, distributed generator owners and other utilities and stakeholders, especially in the distribution network, where the complexity of the network requires higher number of devices than in transmission network.


FEIN Aachen e.V.

Slack Channel FEIN


SMU Open-Source Platform for Synchronized Measurements (Guarnieri Calò Carducci, C.; Pau, M.; Cazal, C.; Ponci, F.; Monti, A.)
Special Issue Sensors and Single-Board Open Source Architectures: Design and Applications, 2022

A Versatile Low-Cost OS-based Phasor Measurement Unit (C. G. C. Carducci, G. Lipari, N. Bosbach, T. D. Raimondo, F. Ponci and A. Monti)
IEEE International Instrumentation and Measurement Technology Conference (I2MTC), Auckland, New Zealand, 2019

Error Model in Single-Board Computer-Based Phasor Measurement Units (C. G. C. Carducci, G. Lipari, N. Giaquinto, F. Ponci and A. Monti)
IEEE Transactions on Instrumentation and Measurement, vol. 69, 2019

Interview with:
Amir Ahmadifar, Research Associate the Institute for Automation of Complex Power Systems
RWTH Aachen University

Interviewer: Amir Ahmadifar, the Low Cost Phasor Measurement Unit is one of the key results of the Platone project whose development was coordinated by the consortium partner RWTH Aachen University. Let´s assume I am a member of the R&D department at a DSO in Germany. I mostly spend my days developing monitoring solutions for the electrical grid for which our DSO is responsible for. As the number of renewables have increased significantly in our grid, we are indeed in an urgent need of increasing local measurements in our grid. During the course of the recent Research Project X, our company got to know (via a research partner) about the so-called Low-Cost PMU which could increase the grid observability for special parts of our grid. Could you please talk a bit about this device?

Amir Ahmadifar: Sure! Our open-source and license free grid management tool might just be what you’re looking for. You can easily fork our solution via GIT and customize the code to your needs. The Low-cost Phasor Measurement Units developed by our organization are devices that increase grid observability, they can do it with a very high time-resolution thanks to high reporting frequency, and with high accuracy. Moreover, these are low-cost devices, while their design of hardware and software is fully open source and designed in a flexible way so that further features and applications can be relatively easily integrated.

Interviewer: I would like to ask a couple of questions about this product: What is the cost of this device? Does it include the hardware and software cost? What about the procurement, installation and commissioning? Any estimate about the total cost?

Amir Ahmadifar: The cost of the PMU itself amounts to 150-250 EUR, depending on how many devices you would like to manufacture and how they are connected to the communication network. These are costs for the hardware, while the software is fully open source thus cost-free. When it comes to procurement, installation and commissioning costs, it depends on existing equipment in the grid nodes, where the PMUs should monitor. For example, in many substations a DSO might already have voltage and current transducers that condition the signals to the range that the PMU is able to measure. If such hardware is not yet in place, additional costs of equipment might range between several hundreds to several thousand of EUR, depending on what type of substation it is, at what voltage level, and what quality of measurements is required.

Interviewer: What are measurements and devices should already be in place for the operation of the low cost PMU?

Amir Ahmadifar: Voltage and current transducers that condition the signals into the range of -10 to 10V AC. Moreover: ethernet connection should be in place or at least mobile network coverage in the desired location.

Interviewer: In which range can the frequency of the measurements be? And does the PMU meet the accuracy requirements of IEEE c37.118 standard?

Amir Ahmadifar: Reporting frequency is configurable and can reach 200 Hz (the highest frequency according to current standards), but also higher reporting frequencies. PMU meets the accuracy requirements; some key test results have been published, while further the laboratory tests confirm compliance to most of the requirements for M and P types PMUs.

Interviewer: What about previous experiences of field installations? Which temperatures can the HW can withstand?

Amir Ahmadifar: Previous installations of low-cost PMU (earlier versions of it) have been performed in multiple European countries including Italy, Romania, Ireland, Germany. No filed tests focused on temperature have been performed earlier. When it comes to lab tests with respect to temperature, some results have been published.

Interviewer: What about support? Are you or somebody at an organization available to grant help if needed? How can I get in touch with you? And can we have also support for the SW development? Like debugging, calibration, etc.? Is the SW a stable version?

Amir Ahmadifar: Support can be provided by FEIN Aachen e.V., which is an association related to our organization that develops and publishes projects including hardware design and software for low-cost PMUs. Contact to this organization would be the best way to get support on SW development, hardware calibration etc., as there are multiple people performing different branches of development who could help. Contact through info@fein-aachen.org or through Slack Channel (see here: fein-aachen.org/contact) should be convenient for an interested future user.

Interviewer: Imagine a case that the device is installed in our grid premises.

Amir Ahmadifar: It can be performed the way it happened in Platone: preconfigured low-cost PMU devices are connected at a desired location (DSO supported by ACS/FEIN performs installations according to its needs). As the next step, connected PMUs are remotely integrated through necessary SW configurations to the desired IT system of a DSO. As the hardware and software is fully open-source and the instructions for installations are available, the integration should be even possible by zhe DSO itself. Even though this solution was created in a scientific project, we made sure that you can always reach out to us. The dedicated support needs to be remunerated though.

Interviewer: Are there any prototypes of this product that could be looked at? What about any repository for the SW?

Amir Ahmadifar: Fundamental steps of integration are (they can be performed independently by an interested party): manufacture dedicated (open source) hardware (many electronics companies on the market can perform it) and buy necessary other hardware (all are easily available on the market). Install (open-source) software according to instructions in the repository. Pay attention to the licenses in the git repository. Further integration of PMU should be performed according to own needs and specifications in the repository. These basic steps can be supported by Fein as described above.

Interviewer: Is there also a specific manual about the device specifications?

Amir Ahmadifar: We offer the functional description on GIT. We could offer you webinars or on-premises workshops as a service if you’re interested.

Interviewer: Thanks a lot for the interview!