Island detection in wind farms in the presence of SVC and STATCOM compensators

Master's Thesis (M.Ss)

Abstract

The tendency to use distributed generation (DG) resources is increasing day by day due to their numerous advantages. The disproportion between the consumption load and the production power will cause the power systems to be operated close to the corresponding nominal capacity, which will seriously aggravate this issue by using FACTS control tools with the aim of postponing the urgent need to develop the current network. In such a situation, the occurrence of any error can cause partial outages, islanding and even complete blackout. Among these situations, the occurrence of islanding conditions is such that a part of the network is used separately from the whole system. In this thesis, in order to quickly detect the created island in the presence of STATCAM and SVC control devices, a new method has been presented that, if it occurs, the created island is revealed in the shortest possible time and the source of scattered production is isolated from the circuit. The proposed method is based on the fact that the transient states of the network parameters in the island state have their own characteristics. Due to the fact that the characteristics of transient signals may not be directly extracted, therefore we will need a process to accurately and quickly detect them. The obtained results show the capability of the proposed method in accurately detecting the islanding state in different conditions. 1. Introduction In today's world, the issue of power supply is very important. Meanwhile, the use of electric energy as a clean source that can be easily produced and transmitted has been of interest. At the beginning of using this energy, diesel generators and similar facilities were used separately to provide power. But with the increase in the power of consumers and the need to standardize values ??such as voltage and frequency, as well as the discussion of system stability, it created a trend towards the construction of large power plants and the construction of large power transmission networks, the advantages of which are relatively constant voltage and frequency and high power that can be delivered. Figure 1-1 shows an electric transmission system.

Figure 1-1 Centralized generation diagram

But due to the ever-increasing growth of industrial, agricultural and household consumers, many problems arose in the generation, transmission and distribution sectors.

Power systems Electric is continuously changing due to the ever-increasing trend of consumption. Due to the restructuring of the electricity industry and its movement towards increased competition and privatization, as well as increased attention to the issue of environmental pollutants, the numerous obstacles and limitations regarding the expansion of networks, such as the heavy costs of developing and building new systems and making the power system smarter, opportunities for the growth and development of electrical energy production technologies such as solar cells, fuel cells, photovoltaic cells, microturbines, and wind turbines. and

With the simultaneous development of power electronic equipment on the one hand and consumer demand for better power quality and higher reliability on the other hand, the electricity industry was pushed towards the use of distributed production. On the other hand, the energy crisis and environmental problems related to fossil energy in recent years have made the use of distributed generation resources (DGs) inevitable. As it was said, new energy sources [2] have different types, and wind energy [3] is one of the most important ones [1]. The use of wind energy takes place in the form of wind farms[4].

The use of distributed generation sources (DG) has various advantages, some of which are [2, 3]:

Working as a grid capacity backup in emergency mode

Using as a starter of complete interruption[5]: DG generation can Create small islands and make network setup easier.

simultaneous production of electricity and heat[6] (CHP): use of heat produced during the production of electrical energy

Peak Sai[7]: helping the system during peak load

reliability: suitable for feeding sensitive loads, increasing system reliability

close to Consumers and reduction of transmission losses

Higher efficiency compared to centralized production sources

Rotational storage[8]

Improving power quality (in some cases)

Delaying investment in the transmission system

Installation and Fast start-up

Improvement of voltage profile

Remarkable advances in power electronics technologies have led to the widespread use of flexible alternating current transmission systems (FACTS) equipment in power networks. The use of these tools has various advantages, one of the most important of which is the postponement of the urgent need to develop and build new networks due to the necessity of providing consumer loads. The quick operation of these controllable equipment provides the management and distribution of active and reactive power to the power grid operators.

Although the use of new energy sources in DGs and less environmental pollution by them compared to centralized production (in some types such as wind and solar energy, there is no environmental pollution) and the advantages that were mentioned, increase the desire to use these sources. has given But you have to deal with the disorders that arise as a result of using them. Due to the fact that distributed generation sources (DG) are directly connected to the distribution network, this has changed the structure of feeding from one side to feeding from both ends, as a result of which, the distribution system will be transformed from inactive [9] to active [10] [4]. This makes it possible to pass power in two directions in some places, which in turn will cause problems in the way the network is used and security issues, especially for distribution network operators. One of these problems is creating an active electrical island in the event of a fault. Also, when a fault occurs, the DG in turn will increase the short-circuit power value, as a result of which the total short-circuit current will increase. The mentioned cases will lead to the invalidity of protective equipment settings [5].

1 Introduction

In today's world, the issue of power supply is very important. Meanwhile, the use of electric energy as a clean source that can be easily produced and transmitted has been of interest. At the beginning of using this energy, diesel generators and similar facilities were used separately to provide power. But with the increase in the power of consumers and the need to standardize values ??such as voltage and frequency, as well as the discussion of system stability, it created a trend towards the construction of large power plants and the construction of large power transmission networks, the advantages of which are relatively constant voltage and frequency and high power that can be delivered. Figure 1-1 shows an electric transmission system.

Figure 1-1 Centralized generation diagram

But due to the ever-increasing growth of industrial, agricultural and household consumers, many problems arose in the generation, transmission and distribution sectors.

Power systems Electric is continuously changing due to the ever-increasing trend of consumption. Due to the restructuring of the electricity industry and its movement towards increased competition and privatization, as well as increased attention to the issue of environmental pollutants, the numerous obstacles and limitations regarding the expansion of networks, such as the heavy costs of developing and building new systems and making the power system smarter, opportunities for the growth and development of electrical energy production technologies such as solar cells, fuel cells, photovoltaic cells, microturbines, and wind turbines. and provided