The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The international standardization community is currently reviewing the supraharmonics distortion limits. These are harmonics which fall in the frequency range 2 to 150 kHz. Power electronics has consolidated as a ubiquitous technology, which also plays a critical role in this subject. Broadly speaking, these HF components are due to the normal operation of electronic converters and the switching techniques...
A stochastic method is presented in this paper to estimate the future voltage unbalance in a low-voltage distribution network with high-penetration of single-phase photovoltaic inverters (PVIs). Location and phase allocation of the PVIs are considered as input parameters for the stochastic simulation. The method has been applied to three different low-voltage networks: two in Sweden and one in Germany...
This paper summarizes the state of part of the discussions in CIGRE/CIRED/IEEE joined working group C4.24, especially where it concerns supraharmonics. There is an increasing interest from the international smart grid standard-setting community in knowledge about harmonics distortion in the frequency range 2 to 150 kHz, referred to as supraharmonics. The paper presents measurements of waveform distortion...
IEEE Std 1564-2014 Guide for Voltage Sag Indices is a new standard that identifies appropriate voltage sag indices and characteristics of electrical power and supply systems as well as the methods for their calculation. This paper presents an overview of IEEE 1564, which was approved as a new standard by IEEE RevCom in March 2014. The paper summarizes the IEEE 1564 methods for quantifying the severity...
This paper contains some thoughts on the relations between power quality and smart grids. It includes some of the, in our opinion, important research and development activities that are needed within power quality as part of the transition to the smart grid.
The paper presents measurements of waveform distortion from six solar-power installations and three wind-power installations. The main emphasis is on the emission of low-order odd harmonics as a function of active-power production. It is concluded that the emission levels are low, that there is in most cases just a weak correlation with active power production, and that every installation is unique...
This paper presents the results of a feasibility study of a virtual power plant (VPP) in central Sweden designed to provide ancillary services to a 50-kV distribution network. The VPP consists of a wind park, hydro plant and reservoir as well as solar PVs and battery energy storage. The 50-kV subtransmission network was modeled in order to evaluate the ancillary services that could be provided by...
The paper presents measurements performed in an urban area in the north of Sweden with two individual houses and on LV side of the distribution transformer supplying these two and ten more houses. Measurements of harmonic and interharmonic groups were performed before and after replacing all existing (mainly incandescent) lamps in all 12 houses with LED lamps. The total power of all lamps was reduced...
The CEER and EURELECTRIC cooperation in the field of quality of electricity supply, involving joint meetings and the participation at the relevant CENELEC Technical Committee, contributed to the results attained in the recent publication of the EN 50160:2010 edition that includes a new voltage dips classification table allowing harmonisation at European level on voltage dips data collection. The generalisation...
This paper introduces three examples of new thinking for addressing the challenges that the power system has to cope with. Such new thinking in combination with new technology will be an important element in the transition to the future electricity network (the —). With overload protection it is important to not remove the overloaded component but the cause of the overload so as to protect the other...
This work presents a comparison study of measurements of power quality, with emphasis on voltage and current distortion, at two locations in the same windpark, located in northern Sweden. Emissions at both locations are compared based on both harmonics and interharmonics. A complete picture of spectrum during the measurement is presented to show the variations of emission in the windpark. Some dominating...
This paper presents the messages to the stakeholders on voltage-dip immunity as extracted by UIE WG2 from CIGRE TB412 [1]. The paper summarizes the main recommendations from this technical brochure in the form of messages towards regulators, standard-setting-organizations, network operators, industrial customers, equipment manufacturers, and power quality monitor manufacturers, researchers.
This paper proposes a novel framework for an intelligent monitoring system that supervises the performance of the future power system. The increased complexity of the power system could endanger the reliability, voltage quality, operational security or resilience of the power system. A distributed structure for such a monitoring system is described and some of the advanced signal processing techniques...
This paper presents measurements of harmonic current emissions up till 2kHz from four different windparks in northern Sweden, all equipped with modern power-electronics converters. The measurement results are presented in different ways, including a method to quantify the impact on the grid and a method to show the variations in the spectrum with time. The results show that there exists different...
This paper applies the hosting-capacity method to a realistic distribution system. Under given circumstances the hosting capacity for Distributed Energy Resources (DER) identifies the degree of DER in power grid that can be accepted without endangering the reliability or quality of power. In this case study two limits setting the hosting capacity were evaluated: overvoltage and overcurrent. Finally...
The installation of distributed generation (DG) introduces challenges to distribution systems operation. The distribution network operator needs to schedule DG outputs considering some constraints, such as DG characteristics, reactive power control mode of generators, automatic voltage regulation, compensator and power quality standard, etc. Based on an optimal power flow model, this paper proposes...
This paper presents the results from the work of joint working group C4.110: a cooperation between CIGRE, CIRED and UIE. Its mandate period stretches from early 2006 through early 2009. The group has addressed several aspects of the immunity of, especially, industrial equipment against voltage dips. Quantifying or specifying equipment performance is part of the assessment or improvement of the voltage-dip...
This paper addresses ways in which distributed generation can be used to the advantage of network operators. A distinction is thereby made between “non-controlled generation” and “controlled generation”. Both types can contribute to an improved performance of the network, where the opportunities for controlled generation are obviously much bigger. It is shown that non-controlled generation can have...
The Customer Dissatisfaction Index (CDI) concept, developed in 2006 by Vattenfall and STRI [1], introduces the service level compliance put into figures in network planning. By using the performance in a load point and the probability that a preset “dissatisfaction” level of security of supply is not fulfilled, it presents a more understandable customer focus. This was presented in an earlier CIRED...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.