21'st century substation design

Substation role in the power system

An electrical substation is a part of an electricity generation, transmission and distribution system where voltage is transformed from high to low or in reverse using transformers. It also serves as a point of connection between various power system elements such as transmission lines, transformers, generators and loads.

To allow for flexibility in connecting the elements, circuit breakers are used as high power switches.

Electric power may flow through several substations between generating plant and consumer, and may be changed in voltage in several steps.

There are different kinds of substation such as Transmission substation, distribution substation, collector substation, switching substation and some other types of substation.

The general functions of a substation may include:

1. Voltage transformation
2. Connection point for transmission lines
3. Switchyard for network configuration
4. Monitoring point for control center
5. Protection of power lines and apparatus
6. Communication with other substations and regional control center

General criteria for substation design

For the substation development to reach its technical and economical potentials, the focus has moved now to studying how substations may enable more intelligence in the network, which is labeled the “smart grid” development.

Figure 1 – Different criteria for the 21st century substation design

It has been concluded that the 21st century substation design should meet the following improved criteria: reliability, security, interoperability, re-configurability, controllability, maintainability, flexibility, reduced cost and environmental impact. An estimate of the importance of the different criteria is shown in Figure 1.

The four major criteria commonly emphasized by substation designers are: reliability, cost, operational flexibility and environment impact.
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Trainig report on transmisson 33/11 kv substation

The training report on transmisson 33/11 kv substation.

The main bus is connected to grid gss danapur Bihar. Now the transmisson line first parallel connected with lightining arrester to diverge surge ,followed by CVT connected parallel

CVT measures voltage and steps down at 110V. A.C. for control panel, at the location a wave trap is connected to carrier communication at higher frequencies.

A current transformer is connected in series with line which measure current and step down current at ratio 800:1 for control panel.

Switchgear equipment is provided, which is the combination of a circuit breaker having an isolator at each end. A transformer is connected to main bus though a bus coupler. The main bus has total capability of 160 MVA for 33 KV, which is subdivided into two transformer capacity of 80 MVA (40MVA+40MVA) parallel connected for 33KV and other two transformer capacity of 80KV (40KV+40KV) are parallel connected for substation.

At both ends of transformer lightning arrester current transformer and switchgear equipment provided. Transformer step downs voltage from 220KV to 33KV.

The main bus is provided with switchgear equipment & a current transformer. This gives way to six feeders transmitting power to danapur. The main bus is connected to jack bus or transfer bus through a bus coupler & 11KV is provided with switchgear equipment. This gives way to feeders transmitting power to railway station danapur .
A step down transformer of 11KV/440V is connected to control panel to provide supply to the equipments of the substation. Capacitor bank is connected to main bus of 11KV. It is provided to improve power factor & voltage profile.
  training report by pratik agrawal can be download from here .

Scada implementation in 220kv substation

SCADA implementation in 220 kV substation

200/110/11kV Shivgiri substation Bijapur is newly installed substation. Under IES project, automation of new substation is done through Substation Automation System (SAS) using IEC 61850. The functions performed by Substation Automation (SA) system are in, general, switch control, data monitoring, protection etc.

A case study on SCADA implementation in 220 kV substation (photo credit: nissi.co.in)

In IEC 61850, these functions are broken into low-level functions called sub-functions.

Each sub-function is performed by the IED installed in the substation. Each IED can perform one or many sub functions. A set of sub-functions is integrated together to realize a substation automation function. These communicate with each other through Local Area Network in the substation.

Figure 1 – Levels defined in IEC 61850

Specific syntax and semantics are defined for communication between sub-functions. All the possible sub-functions have been standardized in IEC 61850. Information produced and required by each substation is given in the IEC 61850 standard.

The sub functions are assigned at three levels as shown in Figure 1 above:

1. Process level
2. Bay level
3. Station level

SCADA equipment in substation

220/110/11kV substation control room is provided with Bay Control and Protection panel and Protection panel by ABB. All the ABB panels are equipped with 4 IEDs used for protection and control.

ABB’s IED 670 series provides reliable, efficient and flexible protection, monitoring and control for all applications in sub-transmission and transmission systems.

IED provides a common powerful hardware platform and an extensive hardware-independent, modular function library. Setting, commissioning and maintenance procedures of all IED are fast and simple. All are similar hence user can learn about one to know them all. These can communicate easily with IEC61850.

The case study of scada pdf can be download from below