SWITCHGEAR(220 kV Sub-station, Ablowal) (Patiala) By: Sunpreet Kaur(Lecturer,EE deptt)

Overview Key diagram of 220 KV Sub station, Ablowal Cables Power transformer Lightening arrester Circuit breaker Isolator Capacitor banks Earthing Wave trap

Key diagram of 220 kV Sub-station, Ablowal

Cables

Power transformer 1. Copper loss Principle of Operation: Mutual inductance Losses in Transformer 1. Copper loss 2. Core loss Hysteresis loss Eddy current loss

Power transformer 220/66kV at Ablowal

Specification of the power transformer Manufactured by ABB Voltage Ratio- 220/66 kV Class OF/AF Transformer Rating- 50-75-100 MVA

Lightening Arrester (Thyrite type) Thyrite type lightening arrester consists of: Series spark gap Non-linear resistor disc in series (These discs are of 15 cm diameter and 19 mm thickness)

Lightening Arrester installed at each phase at 220 kV Sub station, Ablowal

Circuit breaker Vacuum circuit breaker Arc quenching medium- Vacuum Voltage range- 3.3-33kV Breaking capacity- 250-2000MVA SF6 Circuit breaker Arc quenching medium-SF6 gas at 5 kg/cm2 pressure Voltage range- 3.3-765kV Breaking capacity- 1000-50,000 MVA

ISOLATOR Isolators are employed only for isolating circuit when the current has already been interrupted. They operate under no load conditions and are employed on both the sides of the circuit breaker. Isolator consists of insulator posts mounted on a support. There are fixed and moving contacts each made of aluminium.

Capacitor bank

EARTHING: In sub-station it is necessary to make provision for earthing of neutral points, frames of all equipments and other metal works. Earthing can be divided into two parts: Equipment earthing: Equipment earthing deals with earthing of non-current carrying parts of the equipment to ensure safety of personnel and protection against lightening. Neutral earthing: Neutral earthing deals with the earthing of the system neutral to ensure system security and protection.

Earthing at 220 Kv Sub station, Ablowal The earthing system consists of an array of conductors buried horizontally at the depth of 0.5 m. such earthing is called an earthing grid or earth mat. The main steps in the design of the earthing grid are as under: 1. Selection of material and size of the conductor of the grid. 2. Arrangement of the grid conductors. 3. Connection to the grid.

WAVE TRAP It is the effort to utilize the same transmission line between two substations for the purpose of communication. It does the trapping of high frequency communication signals. It is relevant in PLCC system for communication among various sub stations. The wave trap offers high impedance to the high frequency communication signals.

Wave trap installed at 220 kV Sub-station, Ablowal

SCADA system

SLDC (State Load Dispatch Center) To ensure integrated operation of the power system in the state Monitoring and control of system parameters. SLDC keep accounts of the quantity of power transmitted through state grid. Exercising supervision and control over the intra-state transmission system. Analysis of tripping/disturbances and facilitating immediate remedial measures.

SCADA (Supervisory Control and Data Acquisition System) Objectives of SCADA system are: To get real time data from remote locations. To monitor supply during wide voltage and frequency fluctuations. To control power load from generating stations and other sub stations. To monitor PSTCL share in centrally owned power projects.

Components of SCADA system Transducers PT and CT RTU MODEM PLCC LAN Main Server Wave trap

Types of Displays Oneline Display Tabular Display

Oneline Display

Tabular Displays

Historical Data Recording

Utilities used by SCADA system Tagging Trending Alarm

Tagging

Trending The purpose of trending is to reconstruct the post status of SCADA data. GRAPHICAL DISPLAY of DATA. One should select the point for trending and define sampling rate and scale values. It shows us how the different parameters behave in the system.

Thank you!!