Department of Electrical Engineering, Zhejiang University, Hangzhou 310027, China) The bidding principle is to help power plants to obtain greater profits; at the same time, the concept of profit curve is introduced to make a quick evaluation of the profitability of unit bidding.
This article will discuss bidding strategies for power plant units based on the two-part tariff model and the UK POWERPOOL transaction model. The two-part tariff is the electricity price which consists of the electricity price and the capacity electricity price, and forms an on-grid electricity price. The British POWERPOOL is a model currently recognized as an electricity market. It can be simply summarized as cost-based, with the same price as the finalists. In addition, the concept of profit curve is also introduced, which can reflect the profitability of the unit more quickly and visually.
1 Bidding strategy 1.1 Power market trading model The unit's output and electricity price shall be reported to the joint venture center every 0.5 hours of the next day for 48 hours; and the joint ventures shall rank all the declared units according to the electricity load forecast from the low to the high. Under the load of any time period, the unit selected last time by the sequencing is the marginal unit, and its price is the system marginal price for that period; all units that are selected in this period will receive the same feed-in price as the marginal price. 315 • The electricity market trading center shall announce the forecasted load value for the period and the power trading curve in the previous transaction during the period prior to the commencement of the sub-periodic electricity trading. The power trading curve is a curve that reflects the on-grid tariff according to the system load after each generator set is sorted according to the quotation in a certain period of time, as shown.
Electricity trading curve online price! - = 0.40 yuan / (kW * h), at this time the price of 1000MW units with a price of p = 0.40 yuan / (kW * h) has 200MW of access to the Internet, and the remaining capacity of 800MW has failed to access the Internet. This part of the capacity has a great influence on the quotes of other units, and is defined as follows: the same-price balance capacity refers to the part of the unit capacity whose quota is equal to the on-grid price but fails to generate electricity on the grid; the vacant capacity refers to the quotation is greater than the on-grid price but not the 34th volume. The market bidding strategy discusses the capacity of that part of the unit that can generate electricity online.
600MW, the system has the same price balance capacity of 800MW; in the load! 2 = 4400MW, the same price balance capacity is zero. In both cases, the free capacity of the system is 1200 MW including the dotted line).
1.2 Profit formula The unit profit is equal to the unit total income minus the unit cost. Including fixed costs and variable costs).
The electricity price of the pe unit reflects the annual average capacity of the unit which can be converted into a unit and reflects the fixed cost of the unit.) Yuan/(kW-h);! The unit's on-grid electricity at a certain time, kW;! n rated capacity of the unit, kW. 1.3 bidding principle The unit bidding process is fixed and unchanged. Therefore, to maximize "u, only make the unit get the 12 and! As possible the maximum. Therefore, the principle of profit maximization of the unit bidding is: In the unit profitability, should strive for as much capacity as possible to access the Internet, and where possible Under the circumstances, the quotation will be raised to get more profits. In the case of unit loss, as long as the quotation is greater than the electricity price, it is still necessary to strive for as much capacity as possible to access the Internet, reduce the loss, and raise the quotation if appropriate to make the loss smaller. .
A large-scale power plant with multiple large generating units can proceed from the overall interests, and may consider taking part of the on-grid power of individual units to raise the joint price quotation of the on-grid price, so as to increase the overall efficiency of the power plant.
1.4 Bidding main strategy Using the power trading curve to explore the unit's bidding strategy. Considering that under normal circumstances, the load fluctuations during the same period of two similar working days will not be too large, the power trading curve on the first day of the period can be used to guide the unit price of the next day. If there are special circumstances, the load of the period appears. Larger changes should be based on the actual situation of the previous day's power trading curve corresponding changes). Units on the power trading curve can be divided into two units that have been short-listed to obtain on-grid power, and those that have not yet been short-circuited to obtain on-grid electricity. Since the status of the two is different, they are used when competing on the next day's on-grid electricity. The strategy is also different.
1.4.1 Competitive bidding strategy for non-finalized units The non-finalized units are the units that provide the same price balance capacity and free capacity. For non-admitted units, access to electricity on-grid is the sole purpose of participating in bidding. It can be seen that the non-admitted units get the on-grid power through price cuts, which is to squeeze out the short-circuited units with the same capacity into the enclosure. Therefore, the quotation of the non-admitted units must be lower than the quotation of the crowded units with the same capacity and the same capacity. As shown, the system load is! When i=3600MW, a 600MW capacity non-additional unit can only obtain the on-grid power after the quoted price is lower than the quotation of the finalists in the system = 0.35 yuan/(kW.h). Considering that other non-finalists will also take price cuts, the offer should be even lower.
1.4.2 Bidding strategy of the short-listed unit When the same-price balance capacity is large, it is not necessary to consider the size of the spare capacity. As shown in the system load! When 1=3600MW, the on-grid power price of the system is mp=0.40 yuan/(kW*h). At this time, the system's same-price balance capacity is 800MW. The price reduction of the non-immediately-received unit group with a capacity of 800MW will make up the on-grid electricity of the short-listed units. Big threats, if the capacity at this time is also relatively large, the competitive pressure on the finalists will be even greater. Therefore, the finalists have been forced to adopt a price reduction strategy in order to ensure the on-grid electricity.
When the same-price balance capacity and spare capacity are small, the unit's bidding strategy is small. As shown, when the system is loaded! When 2=4400MW, the on-grid power price of the system is mp=0.40 yuan/(kW.h), and the same-price balance capacity is just zero; the vacant capacity is 400MW and the 800MW indicated by the dotted line is not taken into account at this moment, and the quoted price is 0.45 yuan/(kW*h). In this case, the bidding of the unit is very favorable and is divided into two types of analysis.
The bidding strategy for the short-listed small units has been finalized. For small power plants with unit capacity less than 100 MW, if the same-price balance capacity is zero and the vacant capacity is also small, raise the quotation P to satisfy PSmp.
b. The bidding strategy for the large units that have been finalized. When the same-price balance capacity is zero, the capacity is greater! The unit G1 with n=600MW is the most profitable. At this time, there is only 400MW of vacant capacity with a quotation of =0.45 yuan/(kW*h). If we do not consider the quotations of spare capacity units, we will raise the quotation of large unit G1 to satisfy pSmp. From the above analysis, it can be seen that large units are in the same position. When the balance of the price and the free capacity are both small, you can obtain greater profits by raising the price of the quote, and at the same time, the risks you take are also small.
China Power Bookmark6! ) The unit bidding strategy when the same-price balance capacity is small but the free capacity is large. As shown, when the system is loaded! At 4400 MW, the same-value balance capacity is zero, and the spare capacity is 1 200 MW including the 800 MW indicated by the dashed line). There is a price difference between the lowest quotations for the idling capacity unit and the on-grid electricity price of the system, and large units can use this price difference to increase the quotations to obtain more profits. However, due to the large vacant capacity, the vacant capacity unit price reduction will result in the short-listed units. Because of the greater competitive pressure, there is a greater risk of this type of bidding method, and with this in mind, large units should be cautious when adopting a pricing strategy, and they should also exercise appropriate control over the price range even when bidding, but they have large-capacity clusters. Large power plants can use joint quotations to obtain greater profits as long as they have a small amount of same-price balance, and the risk of big power plants adopting a bidding strategy is less than that of a single large unit.
2 Profit curve With the profit formula 1) the profit of the computer group, in the actual operation of the power plant, it is necessary to calculate the profit for several units for every 0.5 hour of the day, and the calculation amount is too large and the operation is too cumbersome. In order to reduce the amount of calculations, the concept of a profit curve is introduced below as a measure of unit profit.
2.1 Definition of profit curve Analysis formula 1) Can be found: 2, and! 3 For the unit is fixed, so 4 and unit get "-. And!
related.
According to formula 2), one can be made! The abscissa and smp are the ordinates. This is the curve in the first quadrant of the hyperbola. The curve is defined as the profit curve. Obviously, at the top of the curve, 4>0, the unit is profitable; while at the bottom of the curve 4, 4 different values ​​are set, in which a series of curves can be made, as shown by the dashed lines in the figure). That is, it represents the four values ​​obtained by the crew in this operating state.
2.2 Application of Profit Curve 2.2.1 Calculation! If you need to fully utilize the indicated on-grid status, the on-grid tariff, for example, point 100, you can directly use the profit curve to directly calculate the profit of the computer group without using the profit formula, and it is more convenient and easy to determine the profitability.
2.2.2 Discriminating the optimal quotation The profit value of the computer group in the process of unit bidding is mainly to obtain the optimal quotation. Using the profit formula to calculate the profit value of each quotation will require a lot of calculations, but if the profit curve diagram is used, it will become Very fast and convenient.
Assume that the unit's three different offers 1, 2 and 3 put the unit in a, e, f 3 operating states as shown. It can be seen that the unit's on-grid power is about 100 MW under point a operation status, and the profit is between 0 and 1 million yuan/h; and the unit's on-grid power is approximately 200 MW near rated capacity under the operating condition of point e), and the profit is 1.0. ~2.0) million / h; point of operation under the unit's Internet power is slightly less than 200MW, profit between 2.0 ~ 3.0 million / h. Obviously, the operating condition at point f should be optimal, so the unit should use 3 offers.
From the above analysis, we can see that the profit curve can not only be used to calculate the unit profit, but also can quickly, accurately and visually determine the optimal price. Therefore, the profit curve can be used as the standard to measure the unit profitability. Because the unit parameters are basically unchanged, a profit curve is generated for each unit. Each time the unit participates in the bidding, the profit curve can be used to measure the profitability of the unit. This not only avoids the cumbersome calculation of the profit formula, but also increases the profitability of the unit. Fast, visual and intuitive, so the profit curve has a certain degree of practicality in guiding the unit bidding. Turning to page 35) Volume 34: Development of Larger Current Transformers in Hall Principles 2001 3rd Table 1 Saturation Magnetic Density Data for Different Open Cores Note: Represents the ampere-turns of the primary current. Magnetic density.
9 2mm long openings, when the primary current is 8640A, the magnetic core of the core is 1.9670T, and the iron core begins to saturate; (6) 12kk3, the size of the core is 155mmx185mmx20mm, there are 12 2mm long openings, when a secondary current For 8640A, the magnetic core of the core is 0.9565T, and the core is not yet saturated.
The saturation current of the iron core does not increase very much. For example, a core with an opening of 10 mm is increased by 5 times than a hole with a diameter of 2 mm, but its saturation current only increases by about 1.7 times. (3) One core of this transformer can have multiple outputs, corresponding to different primary current transformation ratios, and is suitable for interfacing with computer data acquisition systems.
5 Conclusion
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