PRESENTATION ON SUBSTATION DESIGN FRANCIS ARTHUR

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  • Slide 1
  • PRESENTATION ON SUBSTATION DESIGN FRANCIS ARTHUR
  • Slide 2
  • Substation There are four major types of electric substations: Switchyard at a generating station: These facilities connect the generators to the utility grid and also provide off-site power to the plant. Customer Substation: Functions as the main source of electric power supply for one (or more) business customers. The technical requirements and the business case for this type of facility depend highly on the customers requirements.
  • Slide 3
  • Substation Switching Substation: Facilitate the transfer of bulk power across the network. Their feeders typically originate from generating switchyards. They enable the transmission of large blocks of energy from the generators to the load centers. Distribution Substation: Provide the distribution circuits that directly supply most electric customers.
  • Slide 4
  • Substation Project Triggers Load Growth System Stability System Reliability System Capacity
  • Slide 5
  • Substation Design Challenge Optimal technical performance at least cost. Design Considerations Low life cycle cost Safety Standardization (Equipment and Station Configurations)
  • Slide 6
  • Substation Configurations Single Bus All elements (transformers and transmission lines) are directly connected to one bus Advantages Cost of construction is relatively low Disadvantages Reliability is low Low Operational Flexibility (E.g Outage required on associated element for maintenance of switchgear) Suitable Where: Load & Availability requirements are low
  • Slide 7
  • Substation Configurations Typical Single Line Diagram Typical Layout
  • Slide 8
  • Substation Configurations Main and Transfer Bus All elements (transformers and transmission lines) are directly connected to Main bus Advantages Cost of construction is relatively low Operational Flexibility Higher than single bus scheme due to Transfer Bus and Tie Breaker (Outage is not required on associated element for maintenance of switchgear) Disadvantages Reliability is low Suitable Where: Load & Availability requirements are low
  • Slide 9
  • Substation Configurations Typical Single Line Diagram Typical Layout
  • Slide 10
  • Substation Configurations Double Bus Single Breaker Connects each circuit to two buses, and there is a tie breaker between the buses. Advantages Cost of construction is relatively low Reliability Higher than Main & Transfer bus scheme (Bus fault limited to affected bus due to availability of tie breaker) Disadvantages Low Operational Flexibility (E.g Outage required on associated element for maintenance of switchgear) Suitable Where: Load Transfer & Improved Operating Reliability are Important
  • Slide 11
  • Substation Configurations Typical Layout
  • Slide 12
  • Substation Configurations Double Bus Double Breaker Scheme Involves two breakers and two buses for each element Advantages Increased reliability (Bus fault does not affect any element) Increased Operational Flexibility (E.g No outage required for maintenance of circuit breakers) Disadvantages Cost of construction is relatively high Suitable Where: reliability and availability of the circuit is a high priority.
  • Slide 13
  • Substation Configurations Typical Single Line Diagram
  • Slide 14
  • Substation Configurations Ring Bus All breakers are arranged in a ring with elements connected between two breakers. Advantages Increased reliability (Bus fault limited to affected section & faults to individual elements do not affect others) Increased Operational Flexibility (E.g No outage required on associated element for maintenance of switchgear) Disadvantages Cost of construction is relatively high Suitable Where: reliability and availability of the circuit is a high priority.
  • Slide 15
  • Substation Configurations Typical Single Line Diagram Typical Layout
  • Slide 16
  • Substation Configurations Breaker and a Half Bus Scheme Configured with a circuit between two breakers in a three-breaker line-up with two buses Advantages Increased reliability (Bus fault does not affect any element) Increased Operational Flexibility (E.g No outage required for maintenance of circuit breakers) Disadvantages Cost of construction is relatively high but justifiable due to above advantages Suitable Where: reliability and availability of the circuit is a high priority.
  • Slide 17
  • Substation Configurations Typical Single Line Diagram Typical Layout
  • Slide 18
  • Substation Equipment Categories of Equipment: Switchgear Power Transformers Capacitor Banks & SVC Instrument Transformers Protection and Control Equipment Auxiliaries SCADA and Communication
  • Slide 19
  • Switchgear Disconnector Switch with Earthing Blade Disconnector Switch Without Earthing Blade
  • Slide 20
  • Disconnect Switch Mechanical device that conducts electrical current and provides an open point in a circuit for isolation. Disconnect switches are also installed to by pass breakers or other equipment for maintenance. They are designed for no-load switching. Key Requirements Open and Close reliably whenever necessary Carry current continuously without overheating To remain in the closed position under fault current conditions
  • Slide 21
  • Circuit Breakers Live Tank Dead Tank
  • Slide 22
  • Circuit Breaker A mechanical switching device capable of making, carrying, and breaking currents under normal circuit conditions and also breaking currents under specified abnormal conditions such as a short circuit.
  • Slide 23
  • Surge Arresters Devices deployed to protect power system equipment from being subjected to lightning or switching surges.
  • Slide 24
  • Power Transformer A transformer is an electrical device for converting ac power at a certain voltage level into ac power at a different voltage, but at the same frequency. Inductively couples load to the power system at different voltages.
  • Slide 25
  • Capacitor Banks Deployed for local reactive power compensation at the load. Required for voltage support and reduction of transmission losses.
  • Slide 26
  • Static Var Compensators (SVC) Deployed for dynamic local reactive power compensation at the load. Required for voltage support and reduction of transmission losses. Relies on power electronic and other static controllers to enhance control and increase power transfer capability.
  • Slide 27
  • Instrument Transformers Current Transformer Voltage Transformer
  • Slide 28
  • Instrument Transformers A high precision transformer designed to: Provide input into measurement and/or control equipment. Examples: Voltmeters Ammeters Watthour Meters, Relays. Transform currents or voltages from a usually high value to a value easy to handle by protective relays and instruments.
  • Slide 29
  • Protection & Control Equipment
  • Slide 30
  • Dedicated Protection panels for transmission lines, power transformers or capacitor banks. Protection Equipment ensure speedy isolation of equipment in the event of fault by initiating commands to circuit breakers based on set current or voltage limits. Control Equipment facilitate the control of switchgear either from the control room or at the switchyard.
  • Slide 31
  • Substation Auxiliaries Substation auxiliaries encompass all systems that make the operating voltages of 415Vac, 125Vdc and 48Vdc available at the substation. It includes the following: Auxiliary Transformers (usually 34.5/0.415kV, 100 (or 250kVA) Diesel generator sets Solar Power Systems 125Vdc Rectifiers & 125Vdc Battery Banks 48Vdc Rectifiers & 48Vdc Battery Banks Automatic Change over switches AC & DC Distribution Boards
  • Slide 32
  • Substation Auxiliaries Auxiliary Transformer Generator
  • Slide 33
  • Substation Auxiliaries 125Vdc Rectifier Battery Banks
  • Slide 34
  • Substation Auxiliaries 48Vdc Rectifier Change Over Panel
  • Slide 35
  • Rectifier A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction. The process is known as rectification. (Source: Wikipedia)
  • Slide 36
  • Substation Auxiliaries AC Distribution Panel DC Distribution Panel
  • Slide 37
  • SCADA & Communication Power Line Carrier (PLC)
  • Slide 38
  • SCADA & Communication PLC is the superimposition of various signals (ie. data, voice, Fax etc.) on the power line at different frequencies thus relying on the power line as the carrier of the signals. Functions: Provides means of high speed fault clearing through use of communication schemes to confirm faulted line section. Aids in implementation of breaker failure schemes Aids in remote control requirements Goal: To transmit a signal of high quality to the receiving end such that the receiver can interpret the signal.
  • Slide 39
  • SCADA & Communication Tra