Capítulo 2 Globalización en la industria del vestido
2.13 Prácticas ilegales en el comercio de prendas de vestir
In this section, a new methodology for charging the use of network reactive power assets is going to be introduced. This method would be appropriate because the charging of these assets were accounted (UK) for in the calculation of residual tariff. This charging is lacking in that it does not fully represent the physical electrical capability of system performance induced by each individual users. Since nodal voltage is associated to reactive power flow in a system, that relationship is going to be the basis for charging for the use of network reactive power assets.
In addition, some other issues relating to the problem scope as regard to network pricing will be outlined.
3.7.1 Time of Use, Location Specific (TULS) Model
This model added a dimension to the DRM as regard to adding distributed generation, which was previously not catered for. It analyses power flow during maximum load minimum generation at a secured amount as prescribed by P2/6 (security standard documentation), and during minimum load maximum rated generation.
The critical loading of each asset and circuit is determined by employing the use of a DC load flow equivalent to that of the transmission DCLF ICRP transport model. When the loading is highest during maximum load condition, this scenario is referred to as demand dominated and load will be charged accordingly while generation will be rewarded.
Otherwise, the scenario is termed as generation dominated in which generation will be charged and load rewarded. Thereafter, an annuitized forward looking investment costs (£/kW/yr) are, then, evaluated and allocated amongst the nodes. Consequently, this methodology provides demand and generation prices on a consistent basis and the prices reflect the location. In addition, the prices are derived from either crediting or debiting the cost of upstream assets as regard to whether they are generation or demand dominated.
This latter point ensures significant gross payments are made from generators to load or vice versa. One setback is that this model does not account for system security. Also, DC load flow does not consider limitations resulting from voltage, fault levels and reactive power prices are not provided on a consistent basis. The model entails confidential data, therefore, not easier to place it in the public domain.
3.7.2 Distribution ICRP
This pricing approach was established by Bath University conducted for Ofgem to establish the benefits, thereafter, from charging models based on economic principles in
2005. This model has some added dimensions in relation to the transmission pricing paradigm to satisfy the distribution network properties. For this model, each grid supply point is effectively a slack node [62]. In that regard, any withdrawal or injection at this particular supply point will have a zero charge.
This model is a derivative of injecting a 1 MW of load or generation at each node and the power flow at each circuit caused by that injection is compared to the original power flow before injection. The equations below hold
3.7.3 Original Long-run Incremental Cost (LRIC) for voltage pricing
Since this is the model to be used in this work, it is worthwhile to introduce it so as an insight can be drawn from it.
Furong Li et al [47] suggested that LRIC model reflects the asset costs of supporting an increment, in which lines and cables are a function of distance and, also, the horizon when the investment will be needed. Employing the concept in [44], the relationship below then holds:
The above relation (eqn. (3.5)) states that, for a given voltage degradation rate, v, the time horizon, n, will be the time frame for the voltage to grow from current voltage loading level, V, to full loading level, VLimit.
Calculating the time horizon for the case with and without the increment, n and n1 can be established where there are time horizons for with and without increment, respectively.
This results into the relations below
Lastly, the long-run incremental cost (LRIC) is as follows:
The LRIC approach accounts for the VAr compensation assets and, also, recognises both the distance and the utilization of the asset. This approach is fully formulated and explained, in the next chapter.
3.8 Chapter Conclusions
In this chapter, network pricing in UK and other countries are outlined. Further, recent developments in long-run network charging in the UK were also outlined since the method employed in this research work involves this kind of charging principle. Furthermore, proposed LRIC methodology, which is employed for this research work, is introduced.
Any of the pricing approaches (those in actual use) studied in this chapter do not cater for network VAr compensation assets they instead reflect the investment costs incurred in circuits and transformers to support real and reactive power flow. Even though these assets are catered for in the whole charging methodology but their charges do not necessarily represent the actions of each individual user.
It should be noted that most research in reactive power pricing [25-35] reflects the benefits from generation, reflecting the operational cost due to new customers, that is, how they might change network losses, however, they fail to reflect the network VAr compensation asset investment costs to support real and reactive power flow.
It is then against this background that the LRIC methodology is proposed and it is able to reflect both the existing and future network VAr compensation asset costs and it is based on the spare nodal voltage capacity of an existing network. This aforementioned proposed approach fully represents the action of each individual user on the network, therefore, it provides the correct economic signals for each respective user. This approach is also forward looking, locational and, integrating demand and generation.