5. SCADA systems

If2 ¼ In2ch γ<sup>1</sup> ð Þ� lnf

IB ¼ Imk1 þ Ink

 

be a current flowing through the relay current, as shown Figure 6.

The effect of this current has been in breaking the relay.

Micro-Grids - Applications, Operation, Control and Protection

Current Compensation, and Bergeron line Model.

where I<sup>0</sup>

Figure 6.

120

Differential relay currents at the external fault.

As and I<sup>0</sup>

Un2 Zc2

�If1ch γ1l ð Þ fk

The differential current is the actual measure of relay operation. In addition, the brake current is one of the avoided currents of the mal-tripping differential relay.

˙

The effects of the capacitive current can be cancelling with any of the use of the following techniques. Shunt Reactor, Phasor Compensation algorithm, Capacitor

In reality, the proposal is a reliable method for the protection system. Since each current transformer and circuit breaker can only declare a line, it is usual to protect by the use of two side current transformers and circuit breakers. The currents on both sides were compared. Under normal conditions or for defects outside the protected area, the current Bas-Bar A is equal to the current Bas-Bar B. Thus, the currents in the secondary current transformer were equal; no current flowed through the relay current. If a fault occurs in the protected zone, the secondary transformer currents of Bas-Bar A and Bas-Bar B will not be the same, and there will

The differential protection ratio, by using a multi-slope feature of the relay was inserted into the new relay for its excellent compromise between reliability and sensitivity. The components of the relay compared the different current Idiff (also called operating current), and the restraining current Ibias are expressed in Eqs. (28) and (29) [20–24].

> 

0 As þ I 0 Bs 

Idiff ¼ I 0 As þ I 0 Bs

Ibias ¼ I

Bs are secondary RC phasor currents.

sh γ<sup>1</sup> ð Þ lnf (25)

(28)

<sup>=</sup><sup>2</sup> (29)

(27)

IB ¼ j j Imk1 þ Ink1 (26)

 

It is considered as a means of monitoring and control of power plants also used in renewable power plants and these systems transfer data to the heart of the system which is a master computer and receives orders from many remote terminals; Figure 7 illustrates the structure of the SCADA system, the SCADA system includes the following:


The operation of electricity distribution networks is monitored and controlled by supervisory control and data acquisition (SCADA) systems. SCADA systems are linked through various communications networks such as microwave and optical fiber networks to ensure the functioning of the system. They are used to connect transmission substations with the major generators to facilitate an integrated system. The operation of the methods of communication in the networks of energy is produced by lines along the system with advanced optical networks. The loss of these communication cables is possible and could make the protection and monitoring of the network more complex. Using advanced wireless communication and sensing devices could improve the control and monitoring of the entire system. Intelligent Electronic Devices (IED) for monitoring and control to improve the technology of smart grids, and. IEDs can be installed and distributed within the system to be used for protection and monitoring [24–28]. These devices are

interconnected and can be communicated to the central IED, which is implemented in the substation. On the other hand, IEDs can also monitor and update the electric flow of real-time status and can be used to manage and control the network. Figure 7 shows the monitoring and control by supervisory control and data acquisition system for smart grid technology.
