**4. Technical analysis**

According to the technical activity report, by downloading the monitored data by other industrial devices (such as SEPAMs), leads to the following technical statements assumed by the user [7]: "Event parity: approx. 5% of the total monitored events belong to the USER, and in approx. 95% of cases of origin of the Zonal Electricity Distributor and assumed by the Electricity Transporter.

That is, for month 1 there were 31 memorized events due to Zonal Electricity Distributor, at 2 ... 3 events of own influence - percentage, and for the 2nd month, there were 28 memorized events due to Zonal Electricity Distributor, at 2...3 events of own influence [7].

Obs. A series of additional information was analyzed that is not presented in detail in this chapter, but which competes or influences the proper functioning of the analyzed user, such as:


*Contributing by Monitoring Energy Efficiency to the Development of Optimization Measures… DOI: http://dx.doi.org/10.5772/intechopen.101801*

#### **Figure 21.**

*Events noted in the last half of the 110 kV monitoring period in Electrical Station.*


#### 7.etc.

Thus, for the various events and power quality, the following recommendations were taken into account, presented in the **Table 5**:

The principle of operation/assembly/effects/etc. is similar to the one previously presented on specialized technical literature in the field.

The difference is given by:



*Contributing by Monitoring Energy Efficiency to the Development of Optimization Measures… DOI: http://dx.doi.org/10.5772/intechopen.101801*


**Table 5.**

by passing through the transformer of 110/20 kV that supplies the electric arc furnace; in case of mounting these SVC devices on the 110 kV side, it is to be taken into account only the design data of the SVC system (this additional attenuation is almost null at 110 kV).


Thus, using FACTS devices (SVC or STATCOM) implies [9–11]:

• Flicker

It is a random variation caused by rapid fluctuations of the reactive power in the common power supply point of the steel enterprise. The human eye perceives voltage fluctuation as the change in brightness of light sources.

• Voltage stabilization

The operation of the electric arc can lead to a strong unbalance, especially in the initial stage of starting the melting process. The three-phase asynchronous motors are affected by voltage unbalance. The unbalance of the voltage causes the reduction of the installation's yield, overheating, loud noises, vibrations

and variations of motors'speed. That is why the use of SVC in control mode on each phase of the steel company's power supply system ensures the voltage symmetry and stabilization.

• Reactive power compensation (Q)

The transport of reactive power leads to significant voltage drops and the increase of electric currents in the supply network, decreasing the transport capacity of the active power (P). Public network operators maximize the transport capacity, encouraging users to use local reactive power compensation. SVC maintains the required reactive power (Q) within the limits imposed by the operator, thus avoiding penalties, as well as increasing the efficiency of user activities.

• Harmonic currents reduction

Users with non-linear characteristics such as electric arc furnaces generate harmonic electric currents. Harmonic currents charge the network and lead to voltage distortion. Distorted voltages can cause IT equipment (computers, etc.), control equipment, and other sensitive equipment to malfunction. SVC filter circuits are designed to absorb harmonic load-generated currents such as thyristor-controlled coils (TCRs). THD (Distortion Factor) and the individual level of harmonic currents are limited below the specified (normed) values.

• Energy saving

Reactive power compensation (Q) and increased electricity quality lead to increased active power transmission capacity (P) and reduced active energy losses. Thus, overloading of the power supply network can be avoided. This fact brings benefits for both the company and the environment by a more efficient use of electricity, and a reduction of the need for electricity. It is known that, for every 1 kWh saved, produced in a thermal power plant, the amount of pollutants released into the atmosphere is smaller with about 1 kg of CO2.

• Productivity increase

The SVC system can ensure a practically constant voltage level at the company's power supply bars. This way, it decreases the duration of the melting process and increases productivity. A SVC system limits production interruptions and restarts that require long durations. The electric arc furnaces stabilized by SVC have an important effect on reducing electrode consumption, heat loss and the life of the furnace liner. By increasing the quality of electricity, the demand for equipment is reduced, the lifespan is increased and the costs of maintenance and replacement of some components are reduced.
