Annex Voorbeeldclausules
Annex. From ENTSO-E, Frequently asked questions: Why is the Demand Connection Code not specifying the standards for Power Quality? The term power quality is related to the degree of the distortion of the ideal sinusoidal waveform. This waveform distortion can be mathematically analysed to show that it is equivalent to superimposing additional frequency components onto a pure sinewave. These frequencies are harmonics (integer multiples) of the fundamental power system frequency (50Hz) which starts with the fundamental frequency, and can sometimes propagate outwards from nonlinear loads, causing problems elsewhere on the power system. One of the major effects of power system harmonics is to increase the current in the system. This is particularly the case for the third harmonic (causing resonance), which causes a sharp increase in the zero sequence current, and therefore increases the current in the neutral conductor. This effect can require special consideration in the design of interconnected power systems connecting non-linear loads. In addition to the increased line current, different electrical equipment can suffer the effects from harmonics on the power system connected several kilometres away from the source. For example, electric motors can experience hysteresis loss caused by eddy currents set up in the iron core of the motor. These are proportional to the frequency of the current. Since the harmonics are at higher frequencies, they produce more core loss in a motor than the fundamental frequency would. This results in increased heating of the motor core, which (if excessive) can shorten the life of the motor. The 5th harmonic may cause a counter electromotive force in large grid connected motors which acts in the opposite direction of rotation. ENTSO-E believes the application of Power Quality standards is a cross border subject which can have a significant effect on the system frequency, voltage and currents and the design of the Demand Facility. Power Quality may start within the embedded network and the accumulated effect is visible on the transmission network, where today some synchronous zones do not have this problem on their transmission network, but has the demand topology changes towards the future, the probability increases. Therefore, the impact of and the mitigation countermeasures against Power Quality problems, can be solved through local standards to prevent the cross border effects on the voltage waveform distortions. However, due to the n...
Annex. Toelichting vanuit de ENTSO-E "Frequently asked questions": With regards to simulation models the demand facility is not required to model the entire network or provide updated simulation models for every instance when the DSO network structurally changes. It is also important to note that the simulation models requirements aim at obtaining the indispensable data necessary for the TSO to fulfil its responsibilities in assessing system security in case of defined critical events. The DCC defines a set of requirements applicable to significant grid users hence, where appropriate, simulation models may be necessary to verify required capabilities and to use in all types of studies for continuous evaluation in system planning and operation. Traditionally these models were very simple and were often estimated by the TSO’s. The strong increase of penetration of embedded generation and new requirements such as Demand Side Response introduce a level of complexity concerning demand performance in the system that will require dynamic modelling besides steady state. Therefore the TSO, in order to be able to perform his functions and to guarantee system security, will need to perform different types of studies. The significant grid user shall have the responsibility to provide all data necessary for simulation. Type C Power Generating Modules can be required to provide simulation models to the Relevant Network Operator as prescribed in Article 16 of the Network Code on Requirements for Grid Connection applicable to all Generators. A DSO is expected to have more basic (aggregated) information than the Relevant TSO on smaller types of generation as well. In the future not only generators will play a role in the dynamic response of the system but also DSR. In addition, the move towards a more dynamic network with high levels of international interaction, variable energy generation or demand, and market based changes to demand usage and power production (inherent in a smart grid concept), requires more refined and accurate modelling to ensure fully functional markets and secure operation. In this environment more accurate modelling of non- dynamic aspects of a network, like network components (lines, transformers and cables) and the breakdown of demand users is invaluable in maximising system performance. It is noted that the requirement on simulation models or equivalent information is not mandatory, but a right of the TSO while respecting the provisions of Article 9(3)....
Annex. Niet van toepassing.
1. Voorwoord
Annex. ENTSO-E guidance document for national implementation for network codes on grid connection: "Demand Response – System Frequency Control", 11 October 2017.
Annex. From ENTSO-E, Frequently asked questions: Why is DSR-Reserve a technical and economical efficient solution to support system security? Reserve capability is required by ▇▇▇’▇ to deal with uncertainty ahead of real-time. Traditionally the dominant uncertainty has been demand and unscheduled position for generation. Reserves are typically required to be available from a time when an incident occurs until the time that generation can start up and produce replacement power, e.g. 4 hours for CCGTs. TSO’s define reserve ancillary services in this context and in real-time operation instructs for reserve services at the lowest cost. Introduction of high levels of RES, particularly wind, but also solar PV does significantly change the volume of reserves required. This is linked to the uncertainty in forecasting, e.g. wind. Hence demand which is capable of being deferred for extended periods, preferably up to 4 hours, can in principle be considered for such a service. Demand suitable to deliver these services exists from industry, commercial and at the domestic level. The potential for all these may be explored to give the least societal cost. These services are expected to continue, and to expand in volume to meet the increasing demand, possibly with further market encouragement to widen the geographical base for the products. The types of demand with such potential flexibility (Demand Side Response for Reserve) are temperature controlled, however other devices not yet fully engaged for this purpose includes “wet” white goods (e.g. washers, dishwashers and tumble dryers) and charging of electrical vehicles. In both cases this flexibility will only bring minor or even no inconvenience for most consumers. Therefore this may be an opportunity to develop new DSR services, if adequately rewarded.