When considering the addition of Solar PV, a battery energy storage system (BESS), or an energy management system (EMS), businesses often begin with questions about system capacity, configuration, and investment costs.
However, before selecting equipment, a more fundamental question needs to be addressed:
What conditions and limitations of the factory’s existing electrical system could affect the integration of a new energy solution?
A solution that appears suitable in terms of capacity may not necessarily be compatible with the intended connection point, existing protection equipment, operating arrangements, or production requirements.
This is why a factory electrical system assessment before energy integration is important. It helps businesses identify technical conditions, potential risks, and information gaps before proceeding with detailed engineering design.
For an operating industrial facility, the objective is not simply to determine where new equipment can be installed. It is to understand how the proposed solution will connect, interact, and operate within the existing electrical infrastructure.
Why Is Load Profile Analysis Alone Not Enough to Determine the Integration Approach?
Load profile analysis helps businesses understand when electricity is consumed, when peak demand occurs, and how energy requirements change across production schedules.
This information is essential for evaluating Solar PV, BESS, EMS, and energy efficiency solutions. However, load data alone does not fully describe the technical conditions of a factory’s electrical distribution system.
For example, a load profile may indicate the facility’s power demand at a particular time, but it cannot independently establish whether an existing busbar, electrical distribution board, or cable circuit is suitable for connecting an additional power source.
Answering that question requires operational data to be considered alongside engineering documentation, equipment characteristics, protection arrangements, and site assessment findings.
Businesses that have not yet established a comprehensive understanding of their electricity demand can begin with Industrial Load Profile Analysis Before Energy Investment: What Data Should You Review?.
Load profile analysis helps define the demand. Assessing the existing electrical system helps establish the technical conditions required to integrate a suitable energy solution.
Where Should a Factory Electrical System Assessment Begin?
The first step is to understand how the existing electrical system is configured and operated.
One important reference is the Single-Line Diagram (SLD), which represents the electrical distribution architecture, power sources, transformers, busbars, distribution boards, switching equipment, and major load circuits within its documented scope.
However, an existing drawing should not automatically be assumed to reflect the facility’s current operating conditions.
During its operational life, a factory may have added production lines, modified electrical panels, expanded loads, or changed its power distribution arrangements. Such changes should be checked against as-built documentation and actual site conditions before the information is used as a design basis.
Depending on the proposed solution, an initial assessment may need to examine:
- The power supply arrangement, transformers, and relevant distribution boards.
- The characteristics of switching and protection devices, busbars, and cables within the assessment scope.
- The earthing system and any existing on-site power sources.
- Critical loads and requirements for maintaining operations.
- Modifications already completed or planned for future implementation.
Where documentation is incomplete, the information gaps should be recorded, together with the additional site surveys, measurements, or engineering calculations required.
The objective is not to inspect every component of the factory’s electrical system.
It is to identify and assess the elements directly relevant to the proposed energy solution.
How Does the Connection Point Affect Energy System Integration?
When an additional power source or energy storage system is introduced, its connection point can influence power distribution, protection coordination, metering arrangements, and control requirements.
Connecting a power source to a low-voltage distribution board may involve different assessment conditions from connecting it at another location within the facility’s electrical network.
Before determining the connection point, businesses should clarify the actual electrical configuration, the voltage level at the proposed location, the capabilities of relevant equipment, and the intended operating modes of the new power source.
It is also important to distinguish between the equipment’s connection location within the internal electrical network, the direct connection point of the power source, and the applicable electricity metering or delivery point.
Depending on the technical configuration and electricity purchasing arrangement, these locations may coincide or differ.
For example, during guidance on rooftop solar implementation in Ho Chi Minh City, a representative of Vietnam’s Electricity Authority discussed a facility equipped with a 22/0.4 kV transformer.
If the rooftop solar inverter is connected to a 0.4 kV distribution board downstream of the main air circuit breaker (ACB), the solar source’s direct connection point is at the 0.4 kV low-voltage level, even though the facility purchases electricity at 22 kV.
This example illustrates why the voltage level at which a factory purchases electricity should not automatically be treated as the direct connection voltage of its rooftop solar source.
Source: EVN – Ho Chi Minh City Addresses Challenges in Rooftop Solar Development (Vietnamese).
For rooftop solar projects, whether surplus electricity is intended to be sold may also affect metering and control requirements. These requirements should be determined according to the applicable project circumstances rather than assuming that every installation requires the same zero-export configuration.
For further discussion of surplus-electricity arrangements, see Selling Surplus Rooftop Solar Electricity in Vietnam: What Should Businesses Check Before Implementation?.
The connection point should be determined based on the existing electrical system and operational requirements, not simply on installation convenience.
How Should Electrical Protection and Power Quality Be Assessed?
The suitability of an existing electrical system cannot be determined solely from the nameplate capacity of a transformer or distribution board.
When an additional power source is introduced, the engineering assessment may need to consider equipment current-carrying capacity, current flows under different operating conditions, prospective short-circuit current, and protection coordination.
Depending on the proposed power source and the existing electrical configuration, the assessment may also cover the short-circuit breaking capacity of relevant devices, earthing arrangements, and potential impacts on power quality.
A key question is:
If a fault occurs, can the protection system detect and isolate the affected section in accordance with the intended protection design?
Adding a power source may change certain operating conditions or current distribution characteristics within the electrical system. However, the nature and extent of these effects must be established through engineering analysis appropriate to the specific configuration.
Power quality can also be an important consideration for factories operating sensitive loads or a significant number of power electronic devices.
Relevant conditions may include voltage fluctuations, harmonics, voltage imbalance, or abnormalities already observed during operation.
These issues should not automatically be attributed to Solar PV or BESS. Their causes need to be established through operating data, measurements, and technical assessment before corrective measures are proposed.
The assessment scope should therefore reflect the facility’s characteristics and the risks that need to be managed, rather than applying an identical testing package to every project.
An existing electrical system should not be considered suitable for integration based solely on equipment ratings or the nominal capacity of the proposed power source.
How Should Metering and Control Systems Work with Existing Infrastructure?
For projects involving multiple energy components, equipment selection cannot be separated from the way the overall system will be monitored and controlled.
Businesses need to determine what information must be collected, where measurements should be taken, which components are authorized to issue control commands, and which systems need to exchange information.
If the factory already operates monitoring or control systems, the integration assessment should consider communication interfaces, compatibility, and the division of responsibilities between relevant parties.
A clear distinction must be made between monitoring functions and control functions.
The ability to display information on a dashboard does not automatically mean that a system can control equipment.
Where control functions are included, the design must also consider control authority, operating priorities, command permissions, and safe operating arrangements in the event of equipment faults or communication interruptions.
For example, when Solar PV and BESS are integrated, the control strategy should define the storage system’s operational objectives, charging and discharging conditions, and coordination with solar generation and facility loads.
If an EMS is included within the project scope, it may support monitoring and coordination of system components according to the established operating strategy.
However, installing an EMS should not be assumed to resolve every control or power quality requirement automatically.
Applications involving critical loads require a separate assessment of power capacity, required supply duration, connection architecture, and power transfer arrangements.
BESS does not inherently replace a UPS, guarantee uninterrupted power transfer, or provide backup electricity for an entire factory.
For a broader explanation of how generation, storage, loads, and controls can be considered within a common system architecture, see Solar and BESS Integration for Industrial Facilities: Designing Generation, Storage and Load as One Energy System.
How Do Operating Conditions and Safety Requirements Affect Implementation?
For an operating factory, a technically suitable integration concept must still be evaluated against actual production conditions.
Electrical connections, system modifications, and testing activities may require power isolation, equipment access, working space, safety controls, and agreed periods during which parts of the electrical system can be taken out of service.
These conditions should be clarified before finalizing the construction scope and implementation schedule.
Depending on the solution and site conditions, preparation may need to consider energy isolation and control procedures, earthing arrangements, electrical work safety, HSE requirements, fire safety, and relevant conditions imposed by the customer or insurer.
Specific requirements must be determined according to the project scope and applicable regulations rather than assuming they are identical across industrial facilities.
At some factories, scheduled maintenance shutdowns may provide opportunities to complete electrical connection work.
At others, production schedules or critical-load requirements may significantly restrict how installation and commissioning activities can be organized.
For this reason, integration work should not be described as having no impact on production unless the engineering approach, execution method, and necessary operating conditions have been confirmed.
From a project risk management perspective, implementation should consider the full sequence of controls:
Design Control → Equipment Control → Installation QA/QC → Testing & Commissioning → O&M Control
Testing and commissioning requirements should also be considered during the design stage, including the scope of tests, acceptance criteria, responsibilities, and procedures for resolving outstanding issues.
Where a project requires regional or headquarters-level approval, the assessment documentation should provide sufficient clarity on technical conditions, unresolved risks, and the responsibilities of each party.
The actual approval structure must be determined for the individual business.
What Should a Business Receive After the Initial Assessment?
The value of assessing existing electrical infrastructure is not measured by the number of devices inspected or the length of the resulting report.
The assessment should help the business answer a more practical question:
Is there sufficient information to proceed with design, and which conditions have been confirmed or still require verification?
Depending on the agreed scope, the assessment deliverables may include:
- Existing-system documentation and equipment information reviewed within the assessment scope.
- Connection arrangements requiring further consideration and their associated technical conditions.
- Additional measurements or engineering calculations needed before design decisions can be finalized.
- Identified risks, limitations, and operating requirements.
- Responsibilities for providing information, performing verification, and securing necessary approvals.
- Outstanding matters that must be resolved before detailed design.
A useful distinction should be maintained between three categories:
Confirmed information, assumptions requiring verification, and matters that cannot yet be concluded.
This distinction can also support procurement and finance teams when comparing proposals from different providers.
If competing proposals rely on different assumptions about existing equipment, modification requirements, shutdown periods, or commissioning activities, comparing initial costs alone may lead to an incomplete decision.
An effective assessment report should support the next investment or engineering decision, not simply describe the current installation.
Checklist: What Should a Factory Review Before Proceeding with Integration Design?
Before moving into detailed engineering, businesses can use the following six questions to review project readiness.
1. Is the existing-system documentation sufficiently reliable?
Have the electrical drawings, equipment specifications, and relevant site modifications been checked against actual conditions within the assessment scope?
2. Have electrical loads and power sources been assessed in the appropriate operating context?
Does the available data reflect important operating modes, existing power sources, and planned changes to the facility?
3. Has the proposed connection point been clearly identified?
Have the connection location, voltage level, relevant equipment, and applicable technical or metering boundaries been clarified?
4. Have electrical protection and power quality requirements been considered?
Which conditions require further inspection, measurement, or engineering analysis before the integration approach can be confirmed?
5. Have control, safety, and implementation conditions been established?
Have monitoring and control arrangements, abnormal operating scenarios, power isolation requirements, and restrictions on system downtime been sufficiently defined?
6. Are responsibilities and next steps clearly assigned?
Who will provide the required information, verify technical conditions, approve relevant decisions, and resolve outstanding issues before the design is finalized?
Not every question needs a complete answer during the first site assessment.
However, important information gaps should be identified, documented, and assigned for resolution rather than becoming unverified assumptions in the investment proposal.
Assessing Existing Electrical Infrastructure Is the Foundation of a Site-Specific Integration Design
Energy system integration is not simply a matter of adding a generation source, storage system, or management platform to an industrial facility.
The more important task is to establish how the proposed solution will interact with existing electrical infrastructure, under which operating conditions it must perform, what technical limitations need to be addressed, and where responsibilities lie.
At 365Energy, the approach to energy solutions begins with the facility’s operating requirements, available data, and actual site conditions before determining the appropriate technical configuration and project delivery scope.
If your business is considering the integration of Solar PV, BESS, EMS, or other energy solutions, the next step should be to clarify the existing-system documentation, proposed connection arrangement, and technical assessment scope before finalizing the design.
Discuss Your Factory’s Pre-Design Assessment with 365Energy
Disclaimer: This article provides general guidance for preliminary engineering assessment. It does not replace detailed engineering design, inspection results, grid-connection studies, or safety assessments conducted by appropriately qualified and authorized parties. Technical, safety, legal, and procedural requirements must be determined according to the project configuration, site conditions, and applicable regulations at the time of implementation.
References
U.S. Department of Energy (DOE)
Distributed Energy Interconnection Checklist
Federal Distributed Energy Project Implementation – Phase 5: Construction and Performance
International Electrotechnical Commission (IEC)
IEC 60364-4-43:2023 – Protection Against Overcurrent
IEC 60364-4-44:2024 – Protection Against Voltage Disturbances and Electromagnetic Disturbances
The DOE publications are referenced for their approaches to distributed energy project assessment, interconnection, implementation, and commissioning. The IEC publications provide technical references relating to low-voltage electrical installations.
These references do not imply that every listed standard or procedure is mandatory for industrial facilities in Vietnam. Applicability must be established according to the specific project, applicable legal requirements, and relevant contractual or technical conditions.