Power System Studies & Analysis

Reliable power systems are essential for efficient operations, yet many organisations struggle with complex electrical distribution challenges which threaten productivity and employee safety. Issues such as load imbalances, frequent outages, variable power quality, and capacity constraints put assets and personnel at risk while interrupting core processes.

Power System Modelling & Analysis

At Engineering Power Solutions (EPS), we understand the pivotal role power system studies can play in protecting and future-proofing your electrical infrastructure. Our power system studies & analysis delve deep into your electrical infrastructure, identifying issues, and providing bespoke strategies for asset optimisation. This includes but not limited to data collection and analysis, simulations, and creating actionable recommendations.

Our power system consultants utilise advanced software such as ETAP, DIgSILENT Power Factory, and EMTP-RV. With these tools we can establish a “digital twin” of HV and LV electrical power networks. This digital representation allows us to simulate the behaviour of electrical assets under various conditions and facilitates strategic planning and informed decision making.

EPS’s Chartered Electrical Engineers specialise in enhancing the reliability of electrical power distribution systems. We meticulosity identify and resolve any vulnerabilities and non-conformities within your infrastructure that may cause unexpected downtime. Our expertise also extends to optimising load distribution and reducing wasted electricity. The safety of your personnel and electrical assets is our top priority. We work tirelessly to ensure a secure operational environment.


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QDS-Power System Study

Load Flow and Short Circuit Analysis

Load Flow Analysis:
To conduct a comprehensive evaluation of demand, power flow analysis, losses, power factor correction, and voltage drop calculations for AC and DC systems. Count on us to provide accurate analysis that enhances the effectiveness and productivity of your electrical systems.


Unbalanced Load Flow Analysis:
To accurately analyse radial and looped 3-phase and unbalanced 1-phase electrical systems. This analysis enables our engineers to identify and resolve issues pertaining to asymmetrical loads, unbalanced voltages, and potential equipment overloads in existing networks.

Unbalanced load flow analysis is crucial in the design of new installations to ensure efficient handling of uneven loads and asymmetrical conditions from the beginning.


Short Circuit Analysis:
Our comprehensive evaluation aims to detect fault currents, precisely locate potential problems within your system, and reduce risks by automatically comparing results with equipment ratings.   We have the capability to perform evaluations for electrical networks in both onshore (IEC 60909) and marine/offshore (IEC 61363) environments, guaranteeing the dependability and security of your electrical infrastructure.


DC Short Circuit Analysis:
Utilise our DC short circuit analysis services in accordance with the IEC 61660 standards.   We evaluate crucial variables such as the rate at which fault current increases, the maximum fault current, the time it takes for the system to reach its peak, and the conditions that remain constant over time.   In addition, we possess extensive knowledge in battery and charger modelling for Battery Energy Storage Systems (BESS), adhering to IEC standards, to guarantee a thorough assessment of the performance of your DC system.



Protection Studies

Electrical protection calculations diagnose vulnerabilities, improve system reliability, and identify areas for improvement in existing networks. To avoid issues in new installations, careful electrical protection calculations ensures that only the faulted part of the network trips. This proactive approach protects the network from faults and disruptions and optimises the electrical infrastructure from a reliability perspective. These calculations help organisations reduce risks, meet industry standards, and build a resilient power network that can meet current and future demands.

Time-Overcurrent Protection

  • Overcurrent-time diagrams
  • Cable and transformer damage curves
  • Motor starting curves
  • Steady-state response checks
  • Steady-state short-circuit simulation with tracing of individual steps
  • Steady-state tripping times for transient or sub-transient current/voltage values
  • Transient response checks (requires Stability Analysis functions (RMS) or Electromagnetic Transients functions (EMT)

Distance Protection

  • Time-Overcurrent Protection
  • P-Q diagrams and R-X diagrams with support of the display of measured impedance trace
  • Time-distance diagrams, with metric or calculation of zone reach in forward and reverse direction

Arc Flash Energy Calculations

Conducting an arc flash study for both existing and new electrical power networks is crucial for ensuring the safety of personnel and protecting equipment. For existing networks, the study helps identify potential arc flash hazards, assess the level of risk, and implement appropriate safety measures.

By understanding the arc flash incident energy and associated hazards, operators can develop effective safety protocols, provide proper personal protective equipment (PPE), and minimise the risk of injury during maintenance or fault conditions. In the design phase of new electrical power networks, an arc flash study enables engineers to incorporate safety measures and equipment configurations that mitigate potential hazards from the outset. Overall, these studies contribute to a safer working environment, compliance with regulatory standards, and the protection of both personnel and critical electrical infrastructure from the dangers associated with arc flash events.

DC Arc Flash Energy Calculations
Conducting an arc flash study for a DC electrical system, especially in Battery Energy Storage (BES) systems and other DC networks, is essential for ensuring the safety of personnel and the integrity of equipment. These studies help identify potential arc flash hazards associated with DC systems, assess the incident energy levels, and implement appropriate safety measures.

Understanding the risks associated with arc flashes allows operators and engineers to establish effective safety protocols, choose proper personal protective equipment (PPE), and design systems that minimise the impact of potential faults.

With arc flash studies we take a practical approach by carrying out the following steps:

  • Arc flash Energy Calculations Study
  • Arc Flash Mitigation Study (Minimising Protection Settings)
  • Switchgear Risk Assessments
  • Arc Flash Awareness Training

For Battery Energy Storage systems and other DC networks, where high energy levels are involved, an arc flash study is instrumental in creating a safe working environment, preventing injuries, and protecting critical infrastructure. It enables the development of safety practices that are crucial for personnel working on or around DC systems, contributing to compliance with safety standards and regulations in the evolving landscape of renewable energy technologies.

G5/5 Harmonic Studies

By obtaining existing Distributed Network Operator harmonic data and data that we can measure using data loggers we can accurately model the harmonics, resonance, and inter-harmonics around the power system network.

Harmonic modelling helps diagnose and fix voltage distortion and equipment compatibility issues in existing networks by analysing the harmonic profile. Engineers can predict and address harmonic resonance, reduce the risk of equipment failures, and optimise the overall performance of the power network.

Our proactive approach improves electrical infrastructure reliability, regulatory compliance, and load efficiency to standards IEEE 519-2014, IEC 61000-3-14, IEC 61000-3-6 and / or Engineering Recommendation ENA G5 issue 5 (G5/5 Harmonics).

  • Harmonic load flow
  • Frequency scan analysis
  • Filter sizing and verification reports
  • Voltage flicker limitation studies
  • Resonance condition identification
  • Frequency dependent modelling
  • Harmonic filter design & sizing
  • Automatic distortion evaluation
  • Inter-harmonic simulation
  • Distortion indices calculation
  • Harmonics plots & report findings
  • Calculation of K-Factors and Loss Factors for 2-winding transformers


P28 Studies

P28/2, also known as voltage fluctuation studies, are relevant to a diverse range of facilities and serve as an important regulatory obligation for Distribution Network Operators (DNOs). These studies aim to prevent any negative impact on the public network caused by a private network, such as voltage flicker or voltage regulation issues.

The studies primarily focus on generation projects and battery storage projects to assess the Step Voltage Change (SVC) resulting from generation trips and the Rapid Voltage Change (RVC) resulting from transformer energisation and power swings in battery storage units.   Nevertheless, these principles can also be applied to sites that experience significant variations in their loads, such as those utilising large pumps and compressors, arc furnaces, winders, and similar equipment.

The most intriguing aspect arises in the context of battery energy storage projects.   These projects, which are new to Distribution Network Operators (DNOs), are causing significant unease among them.   Historically, BESS units were evaluated based on their ability to transition from maximum power import to maximum power export, and from maximum power export to maximum power import within a 1-second timeframe. However, it is now evident that this approach is overly simplistic.

P28 studies may involve a combination of Transient Motor Starting, Transient Stability and Transformer Energisation studies including:

  • Step Voltage Change (SVC)
  • Energy storage using batteries Power Ramps
  • Energy storage using batteries Response from the DC/DR/DM
  • Significant load increment and modification factors
  • Flicker (Pst & Plt)

EPS can conduct a comprehensive P28/2 voltage fluctuation assessment for any site, utilising either DIgSILENT Power Factory or ETAP.

P29 Studies

P29 studies are short for Electrical Networks Associate (ENA) standard P28 ‘Planning Limits For Voltage Unbalance’. In short P29 studies focus on analysing unbalanced load flow (unbalanced phases).

It’s worth understanding this is an uncommon study, which DNOs sometimes request. The study examines how new loads can unbalance the power system’s three phases. Basic power system theory states that all three phases of a power system should be equally balanced to optimise the system and prevent excessive heating and neutral currents. This is problematic for DNOs, hence why the P29 rules exist.

An unbalanced power system can cause G59 protection relays to trip due to a vector shift and phase unbalance.

Most loads connected at 11kV and above are three-phase (motors, generators, 3 phase inverters, etc.), which are balanced and will not change system unbalance. DNOs usually accept a statement or brief report explaining this and do not require anything more formal.

A P29 study is more difficult when a system is connected at LV (rarely at HV) and contains many single-phase loads like domestic housing supplies, electrical trace heating, or industrial lighting systems. Single-phase loads can cause significant unbalance if the electrical designer is not careful. A computer model of the connected loads and an unbalanced load flow analysis to confirm the total unbalance are usually needed to demonstrate compliance with the standard.

It’s nearly impossible to get a balanced LV system, but the goal is to minimise unbalance.

Transient Motor Starting

Transient motor starting analysis is essential for both new and existing electrical power networks to understand motor dynamics during start-up. This analysis identifies voltage dips and mechanical stresses that can affect motor performance in existing or new networks.

Operators can improve system reliability and prevent motor starting failures by understanding and mitigating these transient conditions. Transient motor starting analysis ensures that new electrical power networks are designed to meet motor initiation requirements, minimising voltage dips and determining optimal motor starting sequence depending on the process. This proactive approach optimises motor starting procedures to protect equipment and extend the life and efficiency of the power network, ensuring smooth and reliable operations for a variety of industrial processes.

TMS studies are also used to assist with calculating the motor protection settings for motor protection relays. We generally carry out one or several of following activities for Transient Motor Starting analysis:

  • Single, multiple or sequential motor starting
  • Transient motor starting (synchr./asynchr. motors)
  • Steady-state motor starting
  • Various motor starting methods (reactor, auto-transformer, variable rotor resistance, star delta, etc.)
  • Thermal limit check of cables and transformers
  • Typical & common disturbances & operations actions
  • Transient simulation action for various fault types
  • Simulate split system & combine multiple subsystems
  • Automatic relay actions per settings & system dynamics

Quasi-Dynamic Simulation Studies

Quasi-dynamic simulation aims to accurately represent an electrical system’s temporary effects and changing behaviour. This makes it especially valuable for analysing situations involving sporadic or time-based energy sources.  It aids engineers in evaluating the dynamic reaction of the system in response to varying conditions.

For example, consider a microgrid comprising a combination of photovoltaic (PV) solar panels and a battery storage system.  The objective is to assess the system’s efficiency in response to different levels of solar irradiance and electricity demand fluctuations throughout the day.

Quasi-dynamic simulation provides a comprehensive comprehension of the PV and battery storage system’s interaction with diverse conditions over the course of the day.

Engineers can evaluate the system’s performance, including the battery’s efficiency in mitigating power fluctuations and meeting load requirements during times of limited solar energy production.

Quasi-dynamic simulation is a useful tool for understanding the dynamic characteristics of renewable energy and storage systems. It can assist in designing, optimising, and evaluating the performance of these systems over time.

Transformer Energisation Studies

Performing Transformer Energisation Studies is essential for ensuring the dependable and secure operation of transformers during start-up, whether for existing or new electrical power networks.   These studies are essential for identifying potential problems such as inrush currents, overvoltages, and other transient phenomena that may occur when transformers are energised in existing networks.

Operators can enhance overall system reliability by understanding and mitigating these temporary effects, optimising the energisation and minimising stress on the transformer.   Transformer Energisation Studies are crucial in the context of new installations as they enable the design of protective measures and control strategies to prevent excessive stresses on the transformer and its associated equipment.   By adopting a proactive approach, the energisation process is carefully synchronised with the transformer’s specifications, thereby improving the lifespan and efficiency of the electrical power network.

Transient Stability and Load Shedding

Conducting a Transient Stability and Load Shedding study for both existing and new electrical power networks is essential for ensuring the resilience and stability of the system under dynamic conditions. For existing networks, this study helps identify vulnerabilities to transient disturbances, such as faults or sudden changes in load, and allows for the implementation of effective load shedding strategies.

By assessing the system’s transient stability, operators can enhance reliability and prevent cascading failures during disturbances. In the design phase of new electrical power networks, these studies enable engineers to optimise the system for transient stability from the outset, ensuring that it can withstand and recover from dynamic events. Overall, Transient Stability and Load Shedding studies contribute to a more robust power infrastructure, minimising the risk of widespread outages and enhancing the overall stability and reliability of the electrical network.

Reliability and Contingency Analysis

We provide an efficient and effective reliability assessment of the availability and quality of power throughout your power network. This study calculates expected interruption frequencies and annual interruption costs using network reliability assessment. The importance of each outage is determined by statistical data on outage frequency and duration, protection systems, and network operator resupply efforts. This optimal power restoration process can be analysed and implemented for specific situations.

The total electric interruptions for loads in a power system during an operating period are calculated using statistical methods for the reliability study. The simulation calculates several indices to describe interruptions and their effects. With the reliability analysis, an optimal way to place remote controlled switches (RCS) can be determined to resupply as much demand as possible in the shortest time with a given number.

Generation Adequacy Analysis uses stochastic methods to assess system supply capabilities.

  • Unbalanced system reliability calculation
  • Customer-oriented indices
  • Energy (cost) indices
  • Sensitivity analysis
  • Single & double contingency
  • Looped & radial systems

Electromagnetic Transients (EMT)

EMT simulation can be utilised to address power system transient issues, including lightning, switching and temporary over-voltages, inrush currents, ferro-resonance effects, and sub-synchronous resonance problems.

Depending on the study we use a either DIgSILENT Power Factory, ETAP or Electromagnetic Transients Program EMTP-ATP to perform the following studies:

  • Time-domain analysis or steady-state frequency scan
  • Lightning studies
  • Switching studies
  • Insulation coordination
  • Power electronics
  • HVDC and FACTS (Flexible AC Transmission Systems) Simulations
  • Complex line- and cable parameters (Subsea cables)

Why Choose EPS?

We adhere to strict quality standards with our ISO9001-certified Quality Assurance Policy. Clients can rest assured that our power system consultants provide comprehensive solutions from concept to installation. Our power system studies proactively identify and address vulnerabilities within your electrical infrastructure. By modelling and simulating stress scenarios, we pinpoint upgrade needs and stability improvements, ensuring continuous and safe power to critical operations.