Power Analysis Of Different Distribution Systems

Distribution Systems

1. SINGLE LINE DIAGRAM OF MICROGRID IEEE TEST SYSTEM :

Characteristic Features:

  • Microgrid聽consists of two parts:
  • Solid State Circuit Breakers
  • Micro-power supplies (distributed generations)
  • Sub-station transformer
  • Seven interconnected buses (bus1 is generator bus; buses 5,6,7 are load buses)
  • Three PMT鈥檚
  • Three breakers

The reason behind the selection of SLD:

Due to the rapid growth of electricity demand, grid expansion, and several worldwide blackouts, the vulnerability of large power grids is fully exposed. Therefore the world has now trying to move towards a new power technology-Distributed Generation i-e DG through microgrids. Distributed power generation has outstanding features.

Advantages:

  • flexible power generation
  • Environmental compatibility
  • Better controllability of power system operation
  • Better meet with the power quality
  • Increased reliability of consumers

Feasibility:

聽Microgrids can be installed in a limited area and their results can be studied. Thus it’s feasible to implement this on a limited scale first then move towards a larger scale.

Cost Analysis:

Additional investment is required in this innovative technique.

Cost to benefit ratio must be calculated before installation.

2.聽SINGLE-LINE DIAGRAM OF TEST POWER SYSTEM:

 Fig.2   Sld of a general power system to study different power system parameters

Characteristic Features:

路         3-sync.generators                   9-bus system                         6 lines

路         3 loads                                    3- two winding t/f

Reasons behind the selection of SLD:

This SLD enables the power engineer to have a deep eye on the following aspects:-

路         Analyze the dynamic performance of interconnected power systems.

路         Examines the characteristics of the various components of a power system during normal operating conditions and during disturbances.

路          Explores the detailed mathematical models of system components and analyzes the system behavior using the necessary computational tools.

Advantages:

路聽聽聽聽聽聽聽聽聽Power engineers when finding out the above information then they are well able to model and operate the system in the most economical, reliable, and in an appropriate manner.

路聽聽聽聽聽聽聽聽聽Besides consumers also directly benefitted.

Feasibility:

路聽聽聽聽聽聽聽聽聽This SLD is very simple and easy to implement for the different areas of engineering study.

Cost Analysis:

路聽聽聽聽聽聽聽聽聽Capital required for it is zero percent. It just requires determination and willpower from the Power Engineers side.

3.聽SINGLE LINE DIAGRAM OF聽SMALL DISTRIBUTION 聽聽SYSTEM:

Fig.3  Sld shows a small distribution system

Characteristic Features:

路         Above sld depicts a small distribution system. The electric company distributes power at 69kV, which in turn feeds a 13.8kV distribution system by a 13.8kV, 3-phase, 50-Hz, 20 MVA distribution transformer with an impedance of 8.5%. The 1,000kVA, 6.7% impedance transformer is used to step the voltage down from 13.8kV to 480V.

路聽聽聽聽聽聽聽聽聽Here the point of the study is the understanding of harmonics generation and harmonic voltage arising due to it.

路         Keep in mind that PCC stands for 鈥淧oint of common coupling鈥. It is the electrical connecting point or interface between the utility distribution system and the customer’s or user’s electrical distribution system.

Reasons behind the selection of SLD:

  • Improving the 鈥減ower quality鈥 is the most current topic of discussion among all the distribution Engineers of the world.
  • Until and unless the position of harmonics at each and every component of the power system is not known by the engineers then how could they improve the quality of power? Therefore the above sld is shortlisted.

Advantages:

It equipped the Distribution Engineers with the following flow advantages:-

  • 聽Finds the current harmonics at each and every load in the system.
  • Compare the obtained results with the IEEE Standards ratings.
  • Harmonics are filtered at each individual load and measured easily at the point PCC.
  • Feasibility:

路         Feasibility is 100%

Cost Analysis:

路         Its most economical due to PCC since no need to measure the harmonic distortion at each and every point which ultimately saves the capital

4.  SLD OF A TEST SYSTEM FOR CONTROLLING STATCOM COMPENSATION:

Characteristic Features:

聽The load is grouped at bus 7 and consists of an impedance modeled as an RL load (120MW/32Mvar) supplied by a single generator (250MVA/13.8 kV) and a bulk power system modeled as an infinite bus (10GVA/230kV) by two transmission lines. The generator is powered by a multi-stage steam turbine which is connected to the network through a聽Y聽鈥撀燚聽step-up transformer (350 MVA, 13.8/230 kV).聽The STATCOM/SMES i-e static synchronous compensator and superconducting magnetic energy storage system is placed at the main bus (bus 4) with the purpose of participating in the primary frequency control of the electric system together with the generator, in a case when severe disturbances have occurred.

Reasons behind the selection of this sld:

The SLD is selected since it depicts one of the fundamental concepts of power engineering which is the 鈥減rimary frequency control mechanism.鈥滱 professional Engineer should, in fact, must know about the controlling of frequency and its different methods.

Advantages:

  • The knowledge of frequency, variation in frequency, and its control ultimately made the Power Engineers save the precious equipment and power system from massive damage.
  • In the meantime consumers also benefitted directly.
  • The security and reliability of the power system are enhanced.

Feasibility:

  • STATCOM /SMES is new research.
  • Requires experienced and technically sound persons to be implemented.
  • Sincere and serious efforts are required to be implemented in Pakistan.

Cost Analysis:

  • 聽Firstly the results can be judged by installing STATCOM/SMES at certain locations.
  • If desired results are achieved then can be implemented on large scale.
  • The cost of energy storage devices is not too high so it is economically feasible.

5. NEUTRAL GROUNDING RESISTOR:

聽Fig.5聽聽Sld depicts the protection of equipment through a grounding resistor

Characteristic Features:

  • Neutral聽Grounding聽Resistors聽are聽used聽to聽protect聽power聽transformers,聽power聽generators,聽and聽other associated聽equipment聽in聽your聽power聽systems聽against聽50/60聽Hz聽faults聽(short聽circuits)聽and聽transient聽phenomena聽(lightning).
  • Rated聽current:聽from聽1聽amp聽to聽2000聽A
  • Rated聽voltage:聽from聽0.4聽to聽35kV
  • Rated聽Resistance:聽from聽1聽ohm聽to聽2000聽ohm
  • Rated聽time:聽1聽sec聽to聽continuous聽time聽rating
  • All聽Neutral聽Grounding聽Resistors聽are聽designed,聽rated,聽manufactured,聽and聽tested聽strictly
  • with聽IEEE32.聽Routine聽tests聽performed聽on聽each聽Neutral聽Grounding聽Resistor聽are聽a measurement聽of聽resistance,聽high聽voltage聽power聽frequency,聽insulation聽measurement
  • The standard聽unit聽includes聽the聽stainless聽steel聽resistor聽assembly聽plus聽all聽the聽required聽

insulators,聽internal聽connections,聽and聽hardware聽installed聽in聽a聽standard聽safety聽enclosure.聽NeutralGrounding聽Resistor聽units聽are聽completely聽assembled,聽prewired,聽and聽tested聽at聽our聽facility

Reasons behind the selection of this sld:

  • Protection is a technique that the world engineers move to and a lot of work is still in progress for the security of the power system. That鈥檚 why the SLD has a right to be short-listed here.
  • Protection is the backbone of the power system. Due to this immense significance, this SLD is selected.
  • SLD shows in a very simple manner how can be a transformer or any equipment can be operated safely.

Advantages:

  • A little amount of initial investment protects the most precious machines.
  • Consumers have benefitted directly once again.

Feasibility:

  • The SLD shown above is much more feasible in its nature.
  • The feasibility of this can be better judged by experienced engineers at a particular location of a particular site whether they have to use this or not.

Cost Analysis:

  • Costing PKR=100,000 -10,00,000/-.
  • Professionally and technically it’s wise to invest this amount in order to save the most precious. equipment costing millions of rupees.
  • One-time initial investment saves the power system.
  • Hence security and reliability increased.

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