KR102094137B1 - Method for relaying electric power trading - Google Patents

Abstract

The present invention comprises the steps of configuring a power transaction market based on the collected bidding information by collecting bidding information of a power seller and a power buyer to participate in the power trading by the power trading relay device; And when the power transaction market is constructed, the power transaction relay device determining a power price based on the offer price of the power seller.

Description

Electricity trading relay method {METHOD FOR RELAYING ELECTRIC POWER TRADING}

The present invention relates to a power transaction relay method, and more particularly, to a power transaction relay method for relaying a power transaction by determining an electric power price based on an offer price provided by a power seller and a power consumer in an urban microgrid area. .

The current power transaction method is to purchase electricity produced by several power plants at the Korea Electric Power Exchange wholesale and sell it to general customers at KEPCO. However, in a smart grid or microgrid environment, it is expected that power consumers can trade power with each other as a power seller or power buyer by using bidirectional communication, distributed resources, and energy storage devices.

Considering the characteristics of smart grids or microgrids, such as the balance between supply and demand, the most representative business models that can be promoted in a microgrid environment can be derived in various ways. When the transaction is activated, a demand-response operator can achieve electricity trading between power consumers by relaying electricity bidding / selling in real time to consumers recruited. When the power transaction is completed, the business operator can secure profitability through a difference between the power transaction relay fee, the real-time power supply unit cost, and the actual cost of electricity purchase from the demand-response operator or consumer.

Accordingly, in the related art, a technology has been proposed to determine the risk of power transaction between power consumers with power storage devices installed in a smart grid environment and to conduct power transactions with each other. The risk of power transaction is the reliability of the power supply capability of the power seller estimated through the electricity sales amount, average surplus power, and capacitor capacity information. According to this prior art, power transactions are performed between power consumers in the order of low risk of power transactions.

In addition, a technique for inducing energy savings from an overall perspective by supporting power transaction between a power (re) power seller and a consumer showing different power consumption patterns using an energy management system was also proposed.

However, in the related art, since the standards for demand response providers to promote electricity transactions between consumers are power sales risk and power consumption pattern, they are very helpful in reliability of supply ability and utilization of surplus power, but are relatively important for price factors. Due to lack of consideration, it has not been activated due to low profitability.

On the other hand, the emergence of the electricity trading market entails the implementation of time based pricing. In this environment, power consumers use various devices to change their power consumption patterns, and flexibly adjust supply and demand to generate revenues from changes in power prices. Profitability is the strongest incentive to change power consumption patterns even at the expense of power consumers, so if profitability is secured, consumers can change their power consumption patterns to match the price situation.

In the past, there was a limit to support the emergence of electric power prosumers, as electric power transactions between consumers were based on the difference in electric power sales risk and electric power consumption patterns between consumers. Therefore, it is urgent to improve the market structure and develop related technologies so that more and more consumers can directly and indirectly participate in the trading market and earn money in the microgrid environment.

Background art of the present invention is disclosed in Republic of Korea Patent Publication No. 10-2013-0037559 (2013.04.16).

The present invention was devised to solve the above-mentioned problems, and the object of the present invention is to relay power transactions by determining power prices and relaying power transactions based on the suggested prices provided by electric power sellers and power consumers in the urban microgrid area. Is to provide a way.

Another object of the present invention is to support the emergence of more power prosumers based on the electricity sales price formed in real time, and to support the demand response business operators or power (re) sales operators operating it to generate stable profits, It is to provide a power transaction relaying method that enables power transactions to be carried out regardless of the rise and fall of electricity prices.

Another object of the present invention is applied to a regional-level SG (Smart Grid) spread project to support power transactions between power consumers, and to relay power transactions to maximize profitability in the demand response business (Load Aggregatoion). Is to provide.

Another object of the present invention is to induce power consumption to be stabilized by inducing to reduce demand at a time when power demand is high, to reduce electricity production cost, and to reduce electricity and carbon emissions required for electricity generation. It is to provide a relay method.

In the power transaction relaying method according to an aspect of the present invention, the power trading relay device collects bidding information of a power seller and a power buyer to participate in power trading, and constructs a power trading market based on the collected bidding information. ; And when the power transaction market is constructed, the power transaction relay device determining a power price based on the offer price of the power seller.

In the present invention, the step of constructing the power transaction market includes collecting power consumption per unit time from a smart meter of a power storage device; Deriving the power seller and the power buyer by analyzing and predicting a power consumption pattern based on the power consumption per unit time; Transmitting a power transaction participation message recommending power transaction participation to each of the derived power seller terminal and the derived power buyer terminal; And receiving the bid participation information input through the power transaction participation message from the power seller terminal or the power buyer terminal.

In the present invention, the bid participation information is characterized in that it includes the power price and quantity of the surplus power to be purchased and the transaction time.

The present invention is characterized in that in the step of constructing the power market, the power trading market is configured before a set time from the trading time of the power trading market.

In the present invention, the power price is characterized by determining based on the highest price among the suggested prices of the power seller.

In the present invention, the power price is characterized in that it is determined as the highest value among the values equal to or lower than the offer price of the power purchaser.

In the present invention, the offer price of the power seller is characterized in that it is limited to within a range of a preset upper and lower limit width.

In the present invention, the offer price of the power seller is characterized by being determined by a product of a preset margin of variation and a current power selling price.

In the present invention, the difference between the offer price of the power seller before the variable limit width is applied and the offer price of the power seller after the variable limit width is applied is within the transaction profit or loss minus the current power sale price. Is done.

A power transaction relaying method according to another aspect of the present invention comprises: the power transaction relay device sorting bid price information in the order of highest offer price based on the offer price provided by the power purchaser; And matching the bidding information of the power seller with the bidding information of the power buyer, so that the power transaction relay device determines a power price based on the power seller's offer price.

In the present invention, the bid participation information is characterized in that it includes the power price and quantity of the surplus power to be purchased and the transaction time.

In the present invention, the power price is characterized by determining based on the highest price among the suggested prices of the power seller.

In the present invention, the power price is characterized in that it is determined as the highest value among the values equal to or lower than the offer price of the power purchaser.

In the present invention, the offer price of the power seller is characterized in that it is limited to within a range of a preset upper and lower limit width.

In the present invention, the offer price of the power seller is characterized by being determined by a product of a preset margin of variation and a current power selling price.

In the present invention, the difference between the offer price of the power seller before the variable limit width is applied and the offer price of the power seller after the variable limit width is applied is within the transaction profit or loss minus the current power sale price. Is done.

The present invention supports the emergence of more power prosumers based on the electricity sales price formed in real time, and supports the demand response business operator or the electricity (re) sales operator operating it to generate stable profits, and It enables the power transaction to be carried out regardless of the rise and fall.

The present invention is applied to a regional SG spreading project area in an urban microgrid area to support power transactions between power consumers and to maximize profitability in a demand aggregation (Load Aggregatoion).

The present invention is to stabilize the power supply and demand, reduce the cost of power generation, and reduce the resources and carbon emissions required for power generation by inducing to reduce the demand in times of high power demand.

1 is a diagram conceptually showing a service flow of a power transaction relay device according to an embodiment of the present invention.
2 is a block diagram of a power transaction relay device according to an embodiment of the present invention.
3 is an exemplary diagram of a power transaction participation message according to an embodiment of the present invention.
4 is a flow chart of a power transaction relay method according to an embodiment of the present invention.
5 is a flowchart of a power price determination step according to an embodiment of the present invention.

Hereinafter, a power transaction relaying method according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In this process, the thickness of the lines or the size of components shown in the drawings may be exaggerated for clarity and convenience. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to a user or operator's intention or practice. Therefore, the definition of these terms should be made based on the contents throughout the present specification.

1 is a diagram conceptually showing a service flow of a power transaction relay device according to an embodiment of the present invention, FIG. 2 is a block diagram of a power transaction relay device according to an embodiment of the present invention, and FIG. 3 is a This is an exemplary diagram of a power transaction participation message according to an embodiment of the present invention.

Referring to Figure 1, the power transaction relay device 30 according to an embodiment of the present invention is a power seller terminal 10 possessed by a power buyer who wants to sell power, and a power buyer of a power buyer who wants to purchase power The terminal 20 and the communication network are respectively connected.

The power seller terminal 10 receives a power transaction participation message from the power transaction relay device 30 and transmits bid participation information for power purchase to the power transaction relay device 30.

The power purchaser terminal 20 receives a power transaction participation message from the power transaction relay device 30 and transmits bid participation information for power purchase to the power transaction relay device 30.

Here, the bid participation information may include power price, quantity, and transaction time of surplus power to be purchased.

The power seller terminal 10 and the power buyer terminal 20 may include all of various terminals that input and output various information through a communication network. For example, a personal computer (PC), a smart terminal, a PDA (Pernal Digital Assistant), and a laptop A computer (Laptop Computer) and an IHD (In home display) terminal may be included.

The power trading relay device 30 forms a power trading market between power buyers and power sellers based on bid participation information of a plurality of power prosumers participating in the bidding. When establishing the electricity trading market, the bid price presented by the power seller and the power buyer is considered as the highest priority, and the amount of electricity (transaction volume) is allocated based on the suggested price.

Here, the power prosumer may include both a power seller and a power buyer. This is because in the power transaction, the power seller can be a power buyer, and the power buyer can also be a power seller. Therefore, in this embodiment, the power prosumer is used as a term collectively for both a power seller and a power buyer.

Referring to FIG. 2, the power transaction relay device 30 includes a metering information collection unit 31 for collecting metering data of a power prosumer, a power consumption pattern predictor 32 for analyzing and predicting a consumption pattern of the power prosumer, Based on the prediction result of the power consumption pattern prediction unit 32, a power transaction recommendation unit 33 that derives a potential customer and delivers a power transaction participation message to the terminal of the derived potential customer, bidding information of the power prosumer (sales information, Power transaction market component (34) that collects purchase information and composes the electricity transaction market based on this, power price determination unit (35) that determines power prices based on the collected sales information and purchase information, and profits distribution and integration It includes a power transaction processing unit 36 for processing tasks such as billing.

The metering information collection unit 31 includes charging information such as power surplus in the power storage device of the power prosumer owned by each power prosumer or entrusted by a load management company, charging amount compared to the power surplus, charging cost, charging time, and smart Collect power consumption per unit time from the meter.

The power consumption pattern prediction unit 32 analyzes the power consumption pattern based on the power consumption information for each unit time collected from the metering information collection unit 31, and stores the result value in the power usage information storage unit 37 do. Subsequently, the power consumption pattern prediction unit 32 predicts the power consumption pattern of a potential customer based on the power usage information stored in the power usage information storage unit 37. The prediction results are derived based on the difference or symmetry of the power consumption pattern prediction values of the power seller (candidate) and power buyer (candidate), and the prediction results may include potential customers, that is, power prosumers.

The power transaction recommendation unit 33 transmits a power transaction participation message for recommending a bid to the terminal of the power prosumer derived according to the consumption pattern comparison operation result of the power consumption pattern prediction unit 32 as shown in FIG. 3. The power transaction participation message includes an input request for transaction time, transaction power, bid price information, and the like. The power prosumer who has received the power transaction participation message can respond to the power transaction by inputting the time period, the amount of transaction power, and the bidding price information using the terminal such as his or her IHD, and replying to the power transaction recommendation unit 33. . Moreover, each power prosumer can participate in bidding by directly checking the current electricity sales price fluctuating in real time.

The power trading market composition unit 34 collects bid participation information collected from potential customers and constitutes basic data for constructing a power trading market composed of a power seller and a power buyer. The collected bidding participation information is transmitted to the power price determination unit 35 and used to construct a virtual market for power transactions. The power trading virtual market is configured before the set time from the start time of the power trading virtual market. For example, the electricity trading market, which consists of a group of electricity prosumers who want to sell / purchase electricity at 9:00 am, is constructed until 8:50 minutes just before 9:00 am. When the electricity trading market is constructed in this way, not only the current price of electricity, but also the future price of electricity can be immediately reflected in the market transaction by the forecast of each electric prosumer. Through this, in a market in which prices change in real time, revenue can be generated regardless of whether electricity sales prices fluctuate or fall.

For example, if a bidder named A bids to sell 100 kWh of surplus power at a price of 110 won / kWh at t + 60 an hour after the current time t, the transaction value V becomes 11,000 won (110 Won / kWh; 100kWh). If the time of t + 60 arrives, assuming that the real-time electricity sales price in the electricity market is lower than expected and becomes 100 won, the A bidder can get a profit of 10 won / kWh despite the decrease in real-time electricity sales price.

The power price determination unit 35 serves to match power sellers and consumers in real time by receiving bids from multiple power prosumers. In more detail, the electric power price determination unit 35 determines the electric power price based on the highest price among the suggested prices provided by the electric power seller to proceed with the transaction in order to guarantee the profitability of the electric power seller and to form the electric power transaction market. That is, if the electricity price determination unit 35 is equal to or smaller than the electricity sales amount of the electricity seller located at the i th of the arranged bid information, the electricity buyer j is the total of the electricity purchase amount bid. Purchase from the applicable sales bidding information. In addition, when the amount of electricity purchased by the electricity buyer j is greater than the electricity sales amount of the i-th bid information, the electricity buyer j purchases all the electricity from the entire electricity sales bid information.

For example, if n power sellers bid on the electricity trading market at unit time, and the electricity sales bids (B ^Seller ) they bid are expressed as Equation 1, m electricity buyers participating in the electricity trading market The power purchase bidding information (B ^Buyer ), the information they bid, can be expressed as Equation 2 below.

Here, P _i is the electricity sales price bid by the electricity seller i, and S _i is the electricity sales amount bid by the electricity seller i.

Here, c _j is the power purchase price bid by the power buyer j, d _j is the power purchase amount bid by the power buyer j.

In the bid price (Φ) determined by the operation of the electricity trading market, the bid price (Φ _j ) of the power buyer j is the purchase price (c _j ) bid by the power buyer j among the selling prices (P) bid by the power seller. It is determined to be the largest of the prices that are the same or lower than the purchase price (c _j ) bid by the power buyer j. This is expressed by Equation (3).

If the electricity seller's offer price is compared to the current electricity sale amount or the forecast price, too large price fluctuations may overheat the electricity trading market more than necessary, thereby hindering more participants' electricity trading. It can be operated with a certain level of upper and lower limits. The upper and lower limits can be increased or decreased due to uncertain factors that can affect the value of the transaction, such as the shutdown of the generator part, line failure, and soaring oil prices, or the effects of short- and long-term power market shocks. Therefore, as shown in Equation 4 below, the final suggested price considering the variable limit width is determined by the product of the variable limit width α and the current electricity sales price P (t). The difference between the initial offer price and the final offer price cannot exceed the transaction profit or loss of the power prosumer minus the current price P (t) from the successful bid price (Φ).

Subsequently, the power buyer j purchases power for power sellers who bid at a price equal to or lower than the determined bid price, and the power sales bid information (B _j ^seller ) that is the transaction target with the power buyer j is expressed as Equation (5). Can be.

Therefore, the winning bid amount (A) determined as the power trading market is operated is an n × m dimensional array, as shown in Equation (6). The row of the matrix A in Equation 6 represents the amount of power each power buyer has won from the power sellers, and the column indicates the amount of power sold by the power seller to each power buyer. That is, a _ij represents the amount of power sold by power seller i to power buyer j.

The sales revenue of each power seller participating in the power trading market and the purchase cost of the power buyers can be calculated as shown in Equations 7 and 8.

Here, income _i is the sales revenue of power seller i.

Here, expense _j is the purchase expenditure of the power buyer j.

The power transaction processing unit 36 performs various operations, such as distribution of profits and collection of transaction fees, when an actual transaction is performed after the transaction relationship between the power transaction price and the power seller / purchaser is established. The proceeds generated from the electricity transaction can be combined with the existing electricity rates and billed in an integrated manner, and can also be paid directly by means of cash. The power transaction processing unit 36 monitors the real-time power generation / consumption amount of the region and keeps an eye on the situation, so that each electric power prosumer can discharge the sales volume he promised (bid) at a specific unit time. Secure control over Korea through agreement with consumers.

The power usage information storage unit 37 is the information collected by the metering information collection unit 31, that is, the power surplus and the power surplus in the power storage device of the power prosumer owned by the power prosumer or managed by the load management company. It stores charging information such as the amount of charging, charging cost, charging time, and power consumption per unit time from the smart meter.

Hereinafter, a power transaction relaying method according to an embodiment of the present invention will be described in detail with reference to FIGS. 4 and 5.

4 is a flowchart of a power transaction relaying method according to an embodiment of the present invention, and FIG. 5 is a flowchart of a power price determination step according to an embodiment of the present invention.

Referring to FIG. 4, first, the metering information collection unit 31 is a power surplus in a power storage device of a power prosumer owned by each power prosumer or consigned and managed by a load management company, and a charge amount, charge cost, and charge compared to the power surplus amount. Charge information such as time and power consumption for each unit time from a smart meter are collected (S100). In addition, the metering information collection unit 31 stores the collected information in the power usage information storage unit 37.

Subsequently, the power consumption pattern prediction unit 32 analyzes the power consumption pattern based on the power consumption information for each unit time collected from the metering information collection unit 31 and stores the analysis results in the power usage information storage unit 37 do. Subsequently, the power consumption pattern prediction unit 32 derives a potential customer, that is, a power prosumer, by predicting a power consumption pattern of a potential customer, that is, a power prosumer (S200) based on the power use information stored in the power usage information storage unit 37 do,

When a potential customer is derived by the power consumption pattern prediction unit 32, the power transaction recommendation unit 33 transmits a power transaction participation message recommending a bid to the terminal of the derived power prosumer (S300). Accordingly, the power prosumer can respond to the power transaction by inputting the time period, the amount of transaction power, and the bid price information to his terminal and returning it to the power transaction recommendation unit 33.

In addition, the electric power prosumer can participate in bidding by directly checking the current selling price of electricity fluctuating in real time, not through the above-mentioned electric power transaction participation message.

When a power transaction participation message or a power prosumer participates in a power transaction, the power trading market component 34 collects the bid participation information of each power prosumer and constructs a power trading market composed of a power seller and a power buyer. (S400). In this case, the electricity trading market is configured before the set time from the starting time of the electricity trading market.

When the power trading market is configured by the power trading market component 34, the power price determining unit 35 receives bids from multiple power prosumers and matches power sellers and power buyers in real time to determine power prices ( S500).

That is, as illustrated in FIG. 5, the power price determination unit 35 determines the power price based on the highest price suggested by the power seller and proceeds with the transaction. That is, the power price determination unit 35 sorts the bidding information in the order of the highest suggested price based on the price suggested by the power seller (S510).

Subsequently, the power price determination unit 35 matches the power buyer and the power seller to determine the power price based on the highest price among the prices suggested by the power seller (S520). Here, the power price may be determined based on the highest price among the prices suggested by the power seller, as described above, and is determined to be equal to or lower than the purchase price bid by the power purchaser. Therefore, the electric power purchaser purchases electric power to electric power sellers who bid at a price equal to or lower than the determined successful bid price. In this case, electricity prices are operated with a certain level of upper and lower limits.

The electric power pricing process will be described with reference to Table 1 and FIG. 2.

Bidding participation form (electricity seller) Electric power seller (hopeful) Desired electricity sales (kWh) Desired price (KRW / kWh) Remark Gildong Kim 200 110 won (C + 10) Park Soon Shin 400 85 won (C-15) Youngsil Lee 300 105 won (C + 5) Great Wall 200 95 won (C-5) Jeong Ok Kyun 100 115 won (C + 15)

Bidding participation form (electricity purchaser) Electric power buyer (hopeful) Purchased electricity (kWh) Price (KRW / kWh) Remark Hong Gil Dong 300 115 (C + 15) Admiral Yi 200 110 (C-10) Youngsil Jang 200 105 (C + 5) Lee Seong-gye 200 100 (C) Okgyun Kim 300 95 (C-5)

For example, the total sales bid per unit time of the power storage device distributed in the jurisdiction is 1.2 MWh, and 5 power sellers participate in the bidding as shown in Table 1 below, and the power buyer who wants to purchase power during the unit time In the case of bidding as shown in Table 2, each bidder designates and responds by designating the amount of electricity and price that he or she wants to purchase, and the electric power price determination unit 35 allocates the amount of electric power sold to the electric power purchaser in order to process these orders. . At this time, the bidding price (Φ) is formed by subtracting the amount of the fluctuation amount desired by the electric power seller based on P (t) by directly checking the current electricity sale price or the trend of price fluctuation, and the amount of the fluctuation amount Can not exceed the upper and lower widths given in Equation 4.

Assuming a bid price (Φ) of 100 won and an upper and lower limit of ± 15%, the power price is formed according to the intention of the power seller between 85 and 115 won. Referring to Table 2, Hong Gil-dong has been bidding for 115 won, and the power price determination unit 35 first sorts the order of the present price based on the price suggested by the power buyer, and then matches with 5 power sellers. Conduct. Matching will be performed sequentially until 5 power buyers are completed, but if the total power desired by the power seller is small and cannot be distributed to all power buyers, the power buyer (hopeful) who presented the price less will be bargained. You can.

As an example, since the amount of electricity that Gil Gil-Dong purchased and bid for is 300 kWh, if you search for a power seller that bids for that amount of electricity in Table 1, in the case of Hong Gil-Dong, there are 5 Kim Gil-Dong, Soon-Shin Park, Young-Sil Lee, Jang Seong-Gye, and Jeong Ok-Gyun. The highest price among the suggested rates is 115 won for Jeong Ok-gyun, so the bid price is decided at 115 won considering the price first. Park Soon-Shin, among the five power sellers, offered the lowest price of 85 won, but the transaction price was set at about 30 won and 115 won.

Meanwhile, when the power price is determined as described above, the power transaction processing unit 36 performs power transaction processing after the power price determination (S600). That is, the power transaction processing unit 36 monitors the real-time power generation amount / consumption amount, and monitors the situation, and enables the individual power prosumer to discharge the sales volume he / she promises (bid) at a specific unit time, distribution of profits, transaction fee Perform various actions such as collection.

As described above, this embodiment supports the emergence of more power prosumers based on the electricity sales price formed in real time, and supports the demand-response operators or electricity (re) sellers operating it to generate stable profits, It is possible to conduct electricity transactions regardless of the rise and fall of electricity prices.

In addition, the present embodiment is applied to a regional SG spreading project area in an urban microgrid area to support power transactions between power consumers and to maximize profitability in a load aggregation.

In addition, the present embodiment is intended to stabilize the power supply and demand, reduce the cost of generating electricity, and reduce the resources and carbon emissions required for generating electricity by inducing to reduce the demand at a time when the demand for electricity is high.

The present invention has been described with reference to the embodiment shown in the drawings, but this is only exemplary and those skilled in the art to which the technology belongs can various modifications and equivalent other embodiments from this. Will understand. Therefore, the true technical protection scope of the present invention should be defined by the claims below.

10: power seller terminal
20: power buyer terminal
30: power transaction relay device
31: weighing information collection unit
32: power consumption pattern prediction unit
33: Power Transaction Recommendation Department
34: Power trading market component
35: electricity price determination unit
36: power transaction processing department
37: power usage information storage

Claims (16)

A power transaction relay device collecting bidding information of power sellers and power buyers to participate in power trading, and constructing a power trading market based on the collected bidding information; And
When the power transaction market is formed, the power transaction relay device includes determining a power price based on the offer price of the power seller,
The step of constructing the power transaction market includes: collecting power consumption for each unit time from a smart meter of a power storage device; Deriving the power seller and the power buyer by analyzing and predicting a power consumption pattern based on the power consumption per unit time; Transmitting a power transaction participation message recommending power transaction participation to each of the derived power seller terminal and the derived power buyer terminal; And receiving the bid participation information input through the power transaction participation message from the power seller terminal or the power buyer terminal. delete According to claim 1, The bid participation information
Power transaction relaying method, characterized by including the power price, quantity, and transaction time of the surplus power to be purchased. According to claim 1, In the step of constructing the electricity trading market,
The power trading market is a power trading relay method characterized in that it is configured before the set time from the trading time of the power trading market. The method of claim 1, wherein the power price
Power transaction relay method, characterized in that based on the highest price of the offer price of the power seller. [6] The method of claim 5, wherein the power price is determined as the highest value among values equal to or lower than the offer price of the power purchaser. The method of claim 5, wherein the power seller's offer price is limited within a range of a predetermined upper and lower limit width. [9] The method of claim 7, wherein the electricity seller's offer price is determined by a product of a preset variable margin and a current electricity sales price. 10. The method of claim 8, wherein the difference between the proposed price of the power seller before the variable limit width is applied and the suggested price of the power seller after the variable limit width is applied is within the transaction profit or loss minus the current electricity sales price. Power transaction relay method, characterized in that. delete delete delete delete delete delete delete

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