Distribution System Planning and Studies

Transmission and distribution (T&D) system planning studies can take a variety of forms. Whether a short-term plan used to prepare construction budgets or a 20-year long range plan used to guide system expansion, utilities are realizing tangible gains through proactive management of their systems. The objective of T&D system planning is to develop a thorough understanding of the existing system and prepare a roadmap for near-term and future investments needed to provide adequate, reliable, and economical service to new and existing customers.
The Techlabs team can lead or assist your utility with the following types of system planning studies:

Distribution Studies

• Distribution Long Range Plans

  A distribution system long range plan guides a utility towards an economical and orderly expansion of its distribution system while assuring adequate and efficient service levels over the depreciative life of the facilities. Understanding the utility's long-term requirements helps management  make educated decisions by identifying economically sound solutions in terms of construction costs, system losses, and avoidance of stranded investments.

  
  

  The approach of Techlabs to distribution system long range planning can provide your utility with a number of valuable benefits:

  • An external look at your distribution system by a team of engineering professionals in order to develop the most reliable and economical solutions.

  • Refinement of planning criteria to align with today's expectations for reliability and cost effectiveness.

  • Evaluation of major long-term alternatives such as reviewing the feasibility and economics of converting to a higher primary distribution voltage level, determining the location and size of new substations and tie lines, and primary system line upgrades.

  • Present worth analysis of alternative solutions needed to correct system deficiencies in identified problem areas.

  • Consideration of planned future investment in new technologies such as SCADA, AMR, OMS, and GIS.

  • Review of your distribution system over 10, 20, or more years depending on your specific needs and system growth.

  
  
• Distribution Construction Work Plans

  Short-term distribution system planning provides your utility with specific system improvement projects and construction budgets over the next one to four years. Short-term distribution system plans create an electric service delivery strategy that focuses on improving customer service and maximizing benefits in electric plant investments, automation, and other efficiency tools. Besides traditional considerations, Techlabs specialists can address other issues that impact system plans such as alternate protection schemes, distribution automation, load management, distributed generation, outage management systems, and other technologies.

  
  

  Techlabs's approach to short-term distribution system planning can provide your utility with a number of valuable benefits:

  • An external look at your distribution system by a team of professionals to develop the most reliable and economical solutions.

  • Refinement of planning criteria to align with today's expectations for reliability and cost effectiveness, while also providing guidelines for operational practices.

  • Consideration of non-traditional solutions and available technologies to address system needs.

  • Recommendations for leveraging systems such as SCADA, AMR, GIS, OMS, CIS, and databases.

  • Prioritization of projects that go beyond substations, poles, and wires.

  • Improved project justification.

  
  
• Distribution Sectionalizing and System Protection Studies

  Utility electric distribution systems are sectionalized, which protects them from damaging fault currents by a variety of different protective devices installed across the system. These sectionalizing devices are also paramount in ensuring public safety in the event of a downed conductor or contact with an energized line. Over time, changes to the sectionalizing equipment are required in various locations as a result of new construction and line changes, system configuration changes, and increased fault current levels resulting from substation transformer and transmission line upgrades.

  
  

  To ensure proper protection of your system, each device must be periodically reviewed to evaluate its ability to:

  • Sense the minimum fault current in its zone of protection.

  • Interrupt the maximum fault at its current location.

  • Adequately handle continuous load currents during peak conditions and emergency backfeeding configurations.

  • Coordinate with upstream and downstream devices.

  
  

  The Techlabs team of professionals has many years of experience working with utilities in the area of sectionalizing and system protection. Techlabs can lead or assist your utility with:

  • Evaluating sectionalizing equipment and making recommendations for change where problems are found and where system improvements are being made.

  • Verifying size, type, and recloser settings that are re-installed during maintenance schedules.

  • Assisting with programming of new and existing devices to accommodate current protection requirements.

  
  
• Distribution Sectionalizing Criteria

  Sectionalizing criteria, if properly selected, can have a significantly positive effect on a utility's system reliability. Techlabs is very familiar with industry best practices for sectionalizing criteria and can work with your utility to develop philosophies that confront your specific sectionalizing challenges.

  
  

  Techlabs can assist your utility with the following:

  • Selection of protection zones.
  • Selection of protective device types.
  • Definition of coordination criteria.
  • Definition of loading criteria under normal and emergency conditions.
  • Calculation of minimum ground faults.

  
  

  Selection of fusing philosophies on overhead and underground lines for various types of equipment protection and in different protection zones.

  • Development of electronic recloser and relay setting philosophies.
  • Development of protection schemes for substation transformers and busses.
  • Development of recloser maintenance schedules and records.
  • Selection of distribution automation and smart switching schemes.

  
  
• Distribution Reactive Compensation (Power Factor Correction) Studies

  Distribution Reactive Compensation (Power Factor Correction) Studies
  
  Utilities today are faced with ever more stringent reactive requirements from wholesale power and transmission delivery providers. The need to increase system capacity, improve voltage profiles, and reduce losses necessitates that utilities provide needed reactive compensation at economic voltage levels to maximize the effectiveness of existing distribution systems.
  
  

  Trident Techlabs Private Limited. can lead or assist your utility with preparing reactive compensation studies, commonly referred to as power factor correction studies, to:

  
  

  • Provide a review of the distribution system reactive requirements.
  • Determine the optimum location and size of capacitor installations to achieve desired goals.
  • Determine the necessary mix of fixed and switched capacitor installations to provide only the necessary reactive compensation during peak and low load times.
  • Review potential issues with new capacitor installations such as impacts on AMR/AMI systems, harmonics, interference with communication systems, and potential power quality concerns due to capacitor switching.
  • Integrate the results with other planning studies.

  
  
• Distribution Generation Interconnection Studies

  Distributed generation (DG) interconnections are not new in the utility industry; however, utilities have not necessarily been involved with a significant number of these interconnections to date. Techlabs recognizes that the number of requests utilities are receiving has been increasing over the past few years and will most likely continue to increase as the desire (or, in the case of some states, the requirement) to bring on new renewable energy resources increases. Techlabs can offer a proven team of senior staff consultants to assist with:

  
  

  • Developing interconnection standards, technical requirements, and guidelines.
  • Completing feasibility, system impact, and facility studies.
  • Assisting with the implementation of solutions to facilitate the DG interconnection and parallel operation with the utility's distribution system.
  • Assisting with inspection and testing of installed DG systems.
  • Developing net metering and standby rate tariffs.

  
  

  The interconnection of generation facilities with existing electric distribution systems requires a comprehensive and complete review to identify any adverse system impacts and the interconnection facilities required to accommodate the safe and reliable interconnection and operation of the generation facility. It is common to divide this review process into several steps (a feasibility study, a system impact study, and a facilities study) to provide the involved parties needed information at natural decision points along the way, such as whether to continue toward the implementation of a proposed project. In this manner, the review process becomes more manageable and efficient.

  
  
• Distribution Value of Service Studies

  Value of Service (VOS) studies use advanced survey and statistical techniques to quantify the value of service reliability to end-use consumers. The study results measure the economic losses consumers would bear when a given power outage occurs within a service territory. By identifying the factors (e.g., consumer type, number of employees, household income) that affect economic losses due to service interruptions, VOS studies provide utilities with monetized values for reliability improvements that can be used for evaluating maintenance expenses and capital expenditures associated with reducing outages, ultimately allowing them to more effectively target their resources and investments. VOS studies are useful in transmission and distribution capital planning, maintenance planning, cost of service allocation for reliability-driven investments, and developing strategies to manage curtailment plans.
  The graph below presents example results of a cost-benefit analysis for six projects. In this example, Projects A, C, D, and F have economic benefits to consumers that outweigh project costs. Projects B and E will incur costs greater than the benefits. These results can be used to provide empirical guidance to project prioritization, "go or no go" decisions, and justify rate adjustments.

  
  

  

  
  

  VOS studies can show the economic benefits of reducing outages by substation, feeder, or rate class depending on the objectives of the study.

  • Distribution Substations: This information helps to evaluate the benefits of contemplated transmission or sub-transmission reliability-driven investments. It can assist in prioritizing projects to those most economically valuable to the end-use consumer.
  • Distribution Feeders: This information helps distribution utilities to estimate the benefits of reliability-driven investments (e.g., undergrounding power lines) at the feeder level or load transfer switching schemes. These estimates can be used in a cost-benefit analysis and be used to properly prioritize projects.  This information can be an important input to curtailment strategies.
  • Rate Classes: Different types of consumers incur varying economic costs when outages occur. The economic impacts of a large investment to improve reliability can be estimated by rate class and costs can be allocated across rate classes accurately.

  
  
• Loss Reduction

  The utility industry today has placed a high level of importance on improving efficiency. A proper review of losses experienced on a utility's system can provide valuable insight into ways to manage these losses and improve efficiency while reducing wholesale power costs, improving voltage levels, and freeing up system capacity, potentially reducing costly investment in system improvements.

  
  

  Electrical losses are a reality due to the physics associated with various system components that make up the power system. The effect of losses can be compared to a pipe that is being constricted as demand and ambient air temperature increase, thus limiting the amount of power and energy available at the end-use meter for the same amount of net generation put into the system.

  
  

  Losses during peak times are of particular importance because this is when losses and their costs are typically at their highest. However, in today's world of hourly energy markets and transmission congestion charges, this is not necessarily the case. Utilities now find themselves in a position where having knowledge of the average and incremental cost of power is no longer sufficient to determine the true cost of losses. Instead, the utility needs to be aware of the costs of power and delivery of that power during a myriad of widely divergent costing periods. To properly determine the true cost of losses, knowledge of when losses are being incurred on the system and the magnitude of those losses during different time periods is also needed.  

  
  

  Techlabs is on the leading edge of research efforts to develop innovative techniques to evaluate system losses in today's environment. The goal of these evaluations is to strike an economic balance between investment to lower the true cost of losses when considering all power supply and delivery costing periods, and the benefit derived from those lowered losses. Added detail in terms of the loss locations incurred across the system enhances the understanding of the relative contributions of various system components to total losses. Added detail in terms of the timing of losses allows more precise methods of valuing those losses. In combination, refined loss estimates can lead to improvements in identifying cost-effective loss reduction measures.

  
  
• Arc Flash Studies

  The best approach to electrical safety is to work only on de-energized equipment that has been appropriately locked out and placed in a safe condition. However, due to equipment design or operational limitations, this is not always possible.

  
  

  An arc-flash exposure analysis should be performed in association with or as a continuation of a system protection and coordination study. Results of the protection study are used to calculate the incident energy for assigned working distances throughout the utility.

  
  

  Techlabs will work with you and the power supplier to collect the necessary system data required for the calculations. Techlabs can assist with the following to meet code requirements:

  • Calculating cal/cm² incident energy.
  • Calculating and defining flash protection boundaries (up to 15 kV).
  • Modifying overcurrent device protection schemes to minimize fault current magnitude and duration resulting in lower arc flash incident energy.