Quotation method for maximizing benefit of coal-fired unit on electricity spot market

Abstract

The present invention relates to a quotation method for maximizing the benefit of a coal-fired unit on an electricity spot market. The technical solution is as follows: obtaining, by means of calculation, a fuel cost C1 of a unit, a start cost (comprising a fuel consumption fee C2 for starting and a maintenance fee C3 related to the starting of the unit), an opportunity cost C4 caused by an increase in an equivalent forced outage rate, and a fixed cost C5; and on the basis of the cost components of the unit, using a cost-plus pricing method to perform on-grid quotation. A variable cost and the fixed cost of the unit are comprehensively taken into consideration, such that the cost analysis is more comprehensive; and in view of routine thermal performance test results of the unit, by taking factors such as normal aging of the unit, a thermodynamic device defect and an operation parameter deviation into consideration, and on the basis of D+1 load scheduling, fuel costs of the unit under different loads can be known in advance.

Description

A quotation method for maximizing the benefits of coal-fired units in the electricity spot market Technical Field

[0001] The present invention relates to the fields of electricity spot market and coal-fired unit operating cost accounting, and in particular to a method for determining an on-grid quotation for maximizing the benefits of coal-fired units in the electricity spot market. Background Art

[0002] Spot trading, a key component of the electricity market, is an important means of determining the value of various types of electricity commodities through unit bidding, network constraints, and market demand. It fully reflects the value of electricity as a commodity across time, space, and categories. As market participants, generators must participate in multiple stages, including power generation bidding, unit clearance, and the ancillary services market. Therefore, they must fully understand their own generation costs and provide reasonable grid-connected bids.

[0003] Currently, most power generation companies still use a "planned" approach to production cost accounting, employing "ex post" accounting. These typically use monthly, quarterly, or annual accounting cycles to calculate total power generation costs and the corresponding average cost per kilowatt-hour. However, in the spot market, electricity prices are influenced by a variety of factors, and traditional, crude cost calculation methods are unsuitable for the dynamic and ever-changing market environment.

[0004] Summary of the Invention

[0005] In view of the above situation, in order to overcome the shortcomings of the existing technology, the purpose of the present invention is to provide a quotation method for maximizing the benefits of coal-fired units in the electricity spot market. According to the unit design value, reference is made to the results of daily thermal tests, and comprehensive consideration is given to factors such as normal aging of the unit, defects in thermal equipment, and deviations in operating parameters. At the same time, based on the predicted D+1 day load plan, the fuel cost of the unit under different loads can be known in advance to guide the unit to participate in spot quotation.

[0006] The technical solution adopted in the present invention is:

[0007] A quotation method for maximizing the benefits of coal-fired units in the electricity spot market, characterized by comprising the following steps:

[0008] Step 1: Calculate the fuel cost (coal consumption cost) C1 of the computer group

[0009] Where:

[0010] ——Actual coal consumption for power generation under different loads, in g / kWh;

[0011] P cw ——standard coal price, unit: RMB / t;

[0012] C1——Fuel cost during unit operation, unit: RMB / MWh.

[0013] A. For pure condensing units, the actual coal consumption for power generation under different loads is calculated using the following formula:

[0014] Where:

[0015] b0——designed coal consumption for power generation under different loads, unit: g / kWh;

[0016] Δb1——Increase in coal consumption caused by degradation of unit equipment performance, unit: g / kWh;

[0017] Δb2 – the increase in coal consumption caused by system leakage, auxiliary steam, soot blowing, blowdown, etc. during actual operation of the unit (estimated from historical statistical values), unit: g / kWh;

[0018] C 背压 ——The impact of condenser vacuum changes on coal consumption in different seasons and time periods;

[0019] C 老化 -- The impact of aging equipment on coal consumption as the unit's operating time increases after maintenance;

[0020] The parameters involved in step A include:

[0021] (1) Designed coal consumption for power generation under different loads b0: b0 = K0 + K1 × N 1 +K2×N 2 +K3×N 3 +K4×N 4 (3)

[0022] Where:

[0023] K0, K1, K2, K3, K4 - coefficients, related to the initial / final parameters of the unit, the relative internal efficiency of the steam turbine, and the structure of the thermal system

[0024] N——the day-ahead power generation, in MW;

[0025] (2) Coal consumption increment Δb1 caused by unit equipment performance degradation:

[0026] Determined by actual test values, the deep adjustment condition is determined by actual positive balance data. This method uses linear interpolation calculation, and the formula is as follows:

[0027] Where:

[0028] Δb 1(n-1) , Δb 1(n) ——Known load point N1(n-1) 、N 1(n) The increase in coal consumption, unit: g / kWh;

[0029] K5——coal consumption increment adjustment coefficient under different load rates;

[0030] (3) Back pressure correction coefficient C 背压 :

[0031] Directly use the correction curve provided by the manufacturer for correction. The calculation formula is as follows: C 背压 =K6+K7×p 运行 1 +K8×p 运行 2 +K9×p 运行 3 (5)

[0032] Where:

[0033] K6, K7, K8, K9——coefficients;

[0034] p 运行 ——Operating back pressure of generator at load N, unit: kPa.

[0035] (4) Aging correction factor C 老化 :

[0036] The unit aging correction is calculated using the following formula:

[0037] Where:

[0038] BF——Basic coefficient;

[0039] N——unit power;

[0040] P0——initial pressure of the unit, unit MPa;

[0041] A——unit type, thermal power unit is 1.0;

[0042] B. For heating units, the converted power generation is calculated according to formula (1), where the converted power generation formula is as follows:

[0043] Where:

[0044] N ｇr ——The planned power generation load of the heating unit on the previous day, in MW;

[0045] F gr ——j Heating flow rate at the steam extraction port, unit: t / h;

[0046] H j——j is the steam extraction capacity per unit mass at the steam extraction port, in kJ / kg;

[0047] η jd - electromechanical efficiency,

[0048] ΔN——heating flow converted into power generation, unit MW.

[0049] In the step B, the unit mass steam extraction capacity H of the steam extraction port j is j , the calculation method varies depending on the location of the steam extraction port, as follows:

[0050] (1) When the steam extraction port is before the reheating section, the calculation formula is as follows:

[0051] Where:

[0052] h n ——Turbine exhaust enthalpy, unit: kJ / kg;

[0053] h i ——Heating extraction steam enthalpy, unit: kJ / kg;

[0054] A r ——r is the heat released by the heater drain or the heat absorbed by the feed water, depending on the type of heater, unit: kJ / kg;

[0055] η r ——Steam extraction efficiency at any energy level;

[0056] (2) When the steam extraction port is after the reheating section, the calculation formula is as follows:

[0057] Where:

[0058] σ——heat absorption of 1kg steam in the reheater, J=h zr -h zｌ , unit kJ / kg;

[0059] h zr ——Steam enthalpy in the reheating hot section, unit: kJ / kg;

[0060] h zl ——Steam enthalpy in the reheat cold section, in kJ / kg;

[0061] Step 2: Computer group starts fuel consumption cost C2

[0062] The calculation formula is as follows:

[0063] Where:

[0064] F0——startup consumption of steam turbine, unit: t / h;

[0065] F1 - startup consumption when the boiler is started from a fully cooled state, unit: t / h;

[0066] t s ——downtime, in hours;

[0067] τ0——boiler cooling time constant;

[0068] F s ——Start-up consumption required to restart the unit after shutdown, unit: t / h;

[0069] P cw ——standard coal price, unit: RMB / t;

[0070] C2——unit startup fuel consumption cost, unit yuan.

[0071] Step 3: Computer group startup related maintenance costs C3

[0072] The startup-related maintenance costs are determined by calculating the ratio of the single startup maintenance costs and baseload operation maintenance costs for the group to be used for allocating the total maintenance costs;

[0073] Assuming that the maintenance cost per unit of effective utilization hour is constant, the decomposition steps are as follows: H eu =H u +∑ i T si ×E si (11) C mph =C m ÷H eu (12) C mps,i =E si ×C mph (13) C3=C mph (14)

[0074] Where:

[0075] H eu ——Equivalent to effective utilization hours, unit: h;

[0076] H u ——the average effective utilization hours per year of the last overhaul cycle, in h;

[0077] T si - the annual average number of starts of a certain type during the last overhaul period (i is taken as cold, warm or hot starts);

[0078] Esi ——Convert a single start of a certain type (i) into effective utilization hours, that is, convert the damage caused by a single start into the damage caused by a specific effective utilization hours;

[0079] C m ——the average annual maintenance cost of the last overhaul cycle, in yuan;

[0080] C mps，i ——Maintenance cost per unit effective utilization hour, unit: RMB / h;

[0081] C mph ——Single startup maintenance fee of a certain type, in yuan;

[0082] C3——no-load maintenance cost per hour, in RMB;

[0083] Step 4: Calculate the opportunity cost C4 caused by the increase in the equivalent forced outage rate (EFOR)

[0084] Where:

[0085] ——Average variable cost, unit: RMB / MWh;

[0086] ——Average marginal cost per kilowatt-hour, unit: RMB / MWh;

[0087] ——no-load cost per kilowatt-hour, unit: RMB / MWh;

[0088] ——Average fuel consumption cost, unit: RMB / MWh;

[0089] ——Average material consumption cost (including water, limestone, ammonia injection, etc.), unit: RMB / MWh;

[0090] ——No-load fuel consumption cost per kilowatt-hour, unit: RMB / MWh;

[0091] ——Maintenance cost per kilowatt-hour, unit: RMB / MWh;

[0092] C3——no-load maintenance cost per hour, unit: RMB / h;

[0093] F max ——Power supply fuel consumption of the unit at rated output, in t / h;

[0094] Fmin ——Power supply fuel consumption of the unit at minimum technical output, in t / h;

[0095] G max ——Rated capacity of the unit, in MW;

[0096] G min ——Minimum technical output of the unit, in MW;

[0097] H u ——the average effective utilization hours per year of the last overhaul cycle, in h;

[0098] H r ——the average annual operating hours of the last overhaul cycle, in h;

[0099] F nl ——no-load fuel consumption, unit: t / h;

[0100] P cw ——standard coal price, unit: RMB / t;

[0101] X EFOR ——The amount of EROR promoted by a single start.

[0102] Step 5: Computer Group Fixed Cost C5

[0103] Where:

[0104] C5——depreciation of fixed assets, in yuan;

[0105] C jz ——Basic fixed investment cost per unit capacity, in RMB / MW;

[0106] n——the service life of the unit, in years;

[0107] η czl ——The estimated residual value rate of fixed assets, in %, is calculated as 5%.

[0108] Step 6: Determine the grid-connected price based on the power generation cost

[0109] Combining steps 1 to 5, we can get the unit's power generation cost C, which includes the unit's fuel cost C1, startup costs (including startup fuel consumption costs C2 and unit startup-related maintenance costs C3), opportunity costs C4 caused by an increase in the equivalent forced outage rate, and fixed costs C5. Based on these various cost components, the cost-plus method is used to provide a grid-connected quotation:

[0110] Where:

[0111] O——quote, yuan / kWh

[0112] C——power generation cost, yuan / kWh

[0113] Δ——target profit, yuan / kWh

[0114] 1.13 - VAT rate,

[0115] f——profit rate.

[0116] Compared with the prior art, the method of the present invention has the following advantages:

[0117] 1) Currently, power generation companies often use post-hoc statistical methods to obtain the coal consumption levels of different units to determine the unit's fuel cost. This method has a lag and large errors. The proposed method combines the results of daily thermal test results of the unit, while taking into account factors such as normal unit aging, thermal equipment defects, and operating parameter deviations. Furthermore, based on the D+1 day load plan, the fuel cost of the unit under different loads can be determined in advance.

[0118] 2) The fuel cost calculation method used in the method of the present invention is relatively simple, mostly using historical operating data, without the need to re-perform thermal tests, which greatly reduces the acquisition cost.

[0119] 3) The method of the present invention comprehensively considers the variable cost and fixed cost of the unit, and the cost analysis is more comprehensive. BRIEF DESCRIPTION OF THE DRAWINGS

[0120] FIG1 is a market quotation curve of a power plant contract according to an application example of the present invention. DETAILED DESCRIPTION

[0121] The specific embodiments of the present invention are further described in detail below with reference to the examples.

[0122] The present invention provides a quotation method for maximizing the benefits of coal-fired units in the electricity spot market, comprising the following steps:

[0123] Step 1: Calculate the fuel cost (coal consumption cost) C1 of the computer group

[0124] Where:

[0125] ——Actual coal consumption for power generation under different loads, in g / kWh;

[0126] P cw ——standard coal price, unit: RMB / t;

[0127] C1——Fuel cost during unit operation, unit: RMB / MWh.

[0128] A. For pure condensing units, the actual coal consumption for power generation under different loads is calculated using the following formula:

[0129] Where:

[0130] b0——designed coal consumption for power generation under different loads, unit: g / kWh;

[0131] Δb1——Increase in coal consumption caused by degradation of unit equipment performance, unit: g / kWh;

[0132] Δb2 – the increase in coal consumption caused by system leakage, auxiliary steam, soot blowing, blowdown, etc. during actual operation of the unit (estimated from historical statistical values), unit: g / kWh;

[0133] C 背压 ——The impact of condenser vacuum changes on coal consumption in different seasons and time periods;

[0134] C 老化 -- The impact of aging equipment on coal consumption as the unit's operating time increases after maintenance;

[0135] The parameters involved in step A include:

[0136] (1) Designed coal consumption for power generation under different loads b0: b0 = K0 + K1 × N 1 +K2×N 2 +K3×N 3 +K4×N 4 (twenty four)

[0137] Where:

[0138] K0, K1, K2, K3, K4 - coefficients, related to the initial / final parameters of the unit, the relative internal efficiency of the steam turbine, and the thermal system structure;

[0139] N——Day-ahead power generation, in MW;

[0140] (2) Coal consumption increment Δb1 caused by unit equipment performance degradation:

[0141] Determined by actual test values, the deep adjustment condition is determined by actual positive balance data. This method uses linear interpolation calculation, and the formula is as follows:

[0142] Where:

[0143] Δb 1(n-1) , Δb 1(n) ——Known load point N 1(n-1) 、N 1(n) The increase in coal consumption, unit: g / kWh;

[0144] K5 - Coal consumption increment adjustment coefficient under different load rates, specific values ​​are shown in Table 1;

[0145] Table 1 Coal consumption increment adjustment coefficients for units below 50% THA condition

[0146] (3) Back pressure correction coefficient C 背压 :

[0147] Directly use the correction curve provided by the manufacturer for correction. The calculation formula is as follows: C 背压 =K6+K7×p 运行 1 +K8×p 运行 2 +K9×p 运行 3 (26)

[0148] Where:

[0149] K6, K7, K8, K9——coefficients;

[0150] p 运行 ——Operating back pressure of generator at load N, unit: kPa.

[0151] (4) Aging correction factor C 老化 :

[0152] The unit aging correction is calculated using the following formula (recommended by ASME PTC96 regulations):

[0153] Where:

[0154] BF——Basic coefficient;

[0155] N——unit power;

[0156] P0——initial pressure of the unit, unit MPa;

[0157] A——unit type, thermal power unit is 1.0;

[0158] B. For heating units, the coal consumption calculation formula is as follows: The converted power generation can be calculated according to formula (1), where the converted power generation calculation formula is as follows:

[0159] Where:

[0160] N qr ——The planned power generation load of the heating unit on the previous day, in MW;

[0161] F gr ——j Heating flow rate at the steam extraction port, unit: t / h;

[0162] H j ——j is the steam extraction capacity per unit mass at the steam extraction port, in kJ / kg;

[0163] η jd - electromechanical efficiency,

[0164] ΔN——heating flow converted into power generation, unit MW.

[0165] In the step B, the unit mass steam extraction capacity H of the steam extraction port j is j , the calculation method varies depending on the location of the steam extraction port, as follows:

[0166] (1) When the steam extraction port is before the reheating section, the calculation formula is as follows:

[0167] Where:

[0168] h n ——Turbine exhaust enthalpy, unit: kJ / kg;

[0169] h j ——Heating steam extraction enthalpy, unit: kJ / kg;

[0170] A r ——r is the heat released by the heater drain or the heat absorbed by the feed water, depending on the type of heater, unit: kJ / kg;

[0171] η r ——Steam extraction efficiency at any energy level;

[0172] (2) When the steam extraction port is after the reheating section, the calculation formula is as follows:

[0173] Where:

[0174] σ——heat absorption of 1kg steam in the reheater, σ=h zr -h zl , unit kJ / kg;

[0175] h zr ——Steam enthalpy in the reheating hot section, unit: kJ / kg;

[0176] h zl ——Steam enthalpy in the reheat cold section, in kJ / kg;

[0177] Step 2: Computer group starts fuel consumption cost C2

[0178] The calculation formula is as follows:

[0179] Where:

[0180] F0——startup consumption of steam turbine, unit: t / h;

[0181] F1 - startup consumption when the boiler is started from a fully cooled state, unit: t / h;

[0182] t s ——downtime, in hours;

[0183] τ0——boiler cooling time constant;

[0184] F s ——Start-up consumption required to restart the unit after shutdown, unit: t / h;

[0185] P cw ——standard coal price, unit: RMB / t;

[0186] C2——unit startup fuel consumption cost, unit yuan.

[0187] Step 3: Computer group startup related maintenance costs C3

[0188] The startup-related maintenance costs are determined by calculating the ratio of the single startup maintenance costs and baseload operation maintenance costs for the group to be used for allocating the total maintenance costs;

[0189] Assuming that the maintenance cost per unit of effective utilization hour is constant, the decomposition steps are as follows: H eu =H u +∑ i T si ×E si (32) C mph =C m ÷H eu (33) C mps,i =E si ×C mph (34) C3=C mph (35)

[0190] Where:

[0191] H eu ——Equivalent to effective utilization hours, unit: h;

[0192] H u ——the average effective utilization hours per year of the last overhaul cycle, in h;

[0193] T si- the annual average number of starts of a certain type during the last overhaul period (i is taken as cold, warm or hot starts);

[0194] E si ——The number of effective utilization hours converted from a single start of a certain type (i), that is, the damage caused by a single start is converted into the damage caused by a specific number of effective utilization hours. The specific values ​​are shown in Table 2;

[0195] C m ——the average annual maintenance cost of the last overhaul cycle, in yuan;

[0196] C mps,i ——Maintenance cost per unit effective utilization hour, unit: RMB / h;

[0197] C mph ——Single startup maintenance fee of a certain type, in yuan;

[0198] C3——No-load maintenance cost per hour, in yuan.

[0199] Table 2 Single start equivalent to effective utilization hours E si

[0200] Step 4: Calculate the opportunity cost C4 caused by the increase in the equivalent forced outage rate

[0201] Where:

[0202] ——Average variable cost, unit: RMB / MWh;

[0203] ——Average marginal cost per kilowatt-hour, unit: RMB / MWh;

[0204] ——no-load cost per kilowatt-hour, unit: RMB / MWh;

[0205] ——Average fuel consumption cost, unit: RMB / MWh;

[0206] ——Average material consumption cost (including water, limestone, ammonia injection, etc.), unit: RMB / MWh;

[0207] ——No-load fuel consumption cost per kilowatt-hour, unit: RMB / MWh;

[0208] ——Maintenance cost per kilowatt-hour, unit: RMB / MWh;

[0209] C3——no-load maintenance cost per hour, unit: RMB / h;

[0210] F max ——Power supply fuel consumption of the unit at rated output, in t / h;

[0211] F min ——Power supply fuel consumption of the unit at minimum technical output, in t / h;

[0212] G max ——Rated capacity of the unit, in MW;

[0213] G min ——Minimum technical output of the unit, in MW;

[0214] H u ——the average effective utilization hours per year of the last overhaul cycle, in h;

[0215] H r ——the average annual operating hours of the last overhaul cycle, in h;

[0216] F nl ——no-load fuel consumption, unit: t / h;

[0217] P cw ——standard coal price, unit: RMB / t;

[0218] X EFOR ——The promotion amount of EROR by a single start, the specific data are shown in Table 3;

[0219] Table 3 The promotion amount X of a single start on the unit EFOR EFOR / ‰

[0220] Step 5: Computer Group Fixed Cost C5

[0221] Where:

[0222] C5——depreciation of fixed assets, in yuan;

[0223] C jz ——Basic fixed investment cost per unit capacity, in RMB / MW;

[0224] n——the service life of the unit, in years;

[0225] η czl ——The estimated residual value rate of fixed assets, in %, is calculated as 5%.

[0226] Step 6: Determine the grid-connected price based on the power generation cost

[0227] Combining steps 1 to 5, we can get the unit's power generation cost C, which includes the unit's fuel cost C1, startup costs (fuel costs C2, maintenance costs C3), opportunity costs C4 caused by increased EFOR (equivalent forced outage rate), and fixed costs C5. Based on these various cost components, the cost-plus method is used to provide a grid-connected quotation:

[0228] Where:

[0229] O——quote, yuan / kWh

[0230] C——power generation cost, yuan / kWh

[0231] Δ——target profit, yuan / kWh

[0232] 1.13 - VAT rate,

[0233] f – profit rate;

[0234] The method of the present invention has achieved good technical effects through practical application, and the application examples are as follows:

[0235] For example, consider power plant A, with a rated capacity of 4×600MW, a monthly contracted electricity volume of 2.2 billion kWh, and a load factor of 70%. The standard coal price for its long-term contracted coal is 726.18 yuan / ton, and the contracted volume is 600,000 tons. The standard coal price for its market-provided coal is 620.11 yuan / ton, ensuring supply. Based on the power generation company's contracted performance responsibility letter, a minimum profit margin can be calculated. Setting the profit margin at 10%, the proposed method yields the following quotation function: O = (1.13 + 0.1) × C = 1.23C.

[0236] The power plant contract market quotation curve is shown in Figure 1. By fitting the curve in Figure 1, we can get the plant quotation curve as follows: O = 0.1338 × p 2 -18.635×p+899.91 (22)

[0237] After adopting this model, the monthly power generation income of the power plant throughout the year is shown in Table 4, which increased by RMB 6.7408 million year-on-year, a year-on-year increase of 13.83%.

[0238] Table 4 Statistics of strategy revenue increase in a certain year

Claims

1. A quotation method for maximizing the benefits of coal-fired units in the electricity spot market, characterized by comprising the following steps: Step 1: Calculate the group fuel cost C1 Where: ——Actual coal consumption for power generation under different loads, in g / kWh; P cw ——standard coal price, unit: RMB / t; C1——fuel cost during unit operation, unit: RMB / MWh; A. For pure condensing units, the actual coal consumption for power generation under different loads is calculated using the following formula: Where: b0——designed coal consumption for power generation under different loads, unit: g / kWh; Δb1——Increase in coal consumption caused by degradation of unit equipment performance, unit: g / kWh; Δb2 – the increase in coal consumption caused by system leakage, auxiliary steam, soot blowing, blowdown, etc. during actual operation of the unit (estimated from historical statistical values), unit: g / kWh; C 背压 ——The impact of condenser vacuum changes on coal consumption in different seasons and time periods; C 老化 -- The impact of aging equipment on coal consumption as the unit's operating time increases after maintenance; The parameters involved in step A include: (1) Designed coal consumption for power generation under different loads b0: b0=K0+K1×N 1 +K2×N 2 +K3×N 3 +K4×N 4 (3) Where: K0, K1, K2, K3, K4 - coefficients, related to the initial / final parameters of the unit, the relative internal efficiency of the steam turbine, and the thermal system structure; N——the day-ahead power generation, in MW; (2) Coal consumption increment Δb1 caused by unit equipment performance degradation: Determined by actual test values, the deep adjustment condition is determined by actual positive balance data. This method uses linear interpolation calculation, and the formula is as follows: Where: Δb 1(n-1) , Δb 1(n) ——Known load point N1(n-1) 、N 1(n) The increase in coal consumption, unit: g / kWh; K5——coal consumption increment adjustment coefficient under different load rates; (3) Back pressure correction coefficient C 背压 : Directly use the correction curve provided by the manufacturer for correction. The calculation formula is as follows: C 背压 =K6+K7×p 运行 1 +K8×p 运行 2 +K9×p 运行 3 (5) Where: K6, K7, K8, K9——coefficients; p 运行 ——Operating back pressure of generator at load N, unit: kPa; (4) Aging correction factor C 老化 : The unit aging correction is calculated using the following formula: Where: BF——Basic coefficient; N——unit power; P0——initial pressure of the unit, unit MPa; A——unit type, thermal power unit is 1.0; B. For heating units, the converted power generation can be calculated according to formula (1), where the converted power generation formula is as follows: Where: N gr ——The planned power generation load of the heating unit on the previous day, in MW; F gr ——j Heating flow rate at the steam extraction port, unit: t / h; H j ——j is the steam extraction capacity per unit mass at the steam extraction port, in kJ / kg; η jd - electromechanical efficiency, ΔN——heating flow converted into power generation, unit MW; In the above step B, the work capacity Hj of the steam extraction per unit mass at the j steam extraction port is calculated in different ways depending on the location of the steam extraction port, as follows: (1) When the steam extraction port is before the reheating section, the calculation formula is as follows: Where: hn ——Turbine exhaust enthalpy, unit: kJ / kg; h j ——Heating extraction steam enthalpy, unit: kJ / kg; A r ——r is the heat released by the heater drain or the heat absorbed by the feed water, depending on the type of heater, unit: kJ / kg; η r ——Steam extraction efficiency at any energy level; (2) When the steam extraction port is after the reheating section, the calculation formula is as follows: Where: σ——heat absorption of 1kg steam in the reheater, σ=h zr -h zl , unit kJ / kg; h zr ——Steam enthalpy in the reheating hot section, unit: kJ / kg; h zl ——Steam enthalpy in the reheat cold section, in kJ / kg; Step 2: Computer group starts fuel consumption cost C2 The calculation formula is as follows: Where: F0——startup consumption of steam turbine, unit: t / h; F1 - startup consumption when the boiler is started from a fully cooled state, unit: t / h; t s ——downtime, in hours; τ0——boiler cooling time constant; F s ——Start-up consumption required to restart the unit after shutdown, unit: t / h; P cw ——standard coal price, unit: RMB / t; C2——unit startup fuel consumption cost, unit yuan; Step 3: Computer group startup related maintenance costs C3 The startup-related maintenance costs are determined by calculating the ratio of the single startup maintenance costs and baseload operation maintenance costs for the group to be used for allocating the total maintenance costs; Assuming that the maintenance cost per unit of effective utilization hours is constant, the decomposition steps are as follows: H eu =H u +∑ i T si ×E si (11) C mph =C m÷H eu (12) C mps,i =E si ×C mph (13) C3=C mph (14) Where: H eu ——Equivalent to effective utilization hours, unit: h; H u ——the average effective utilization hours per year of the last overhaul cycle, in h; T si - the annual average number of starts of a certain type during the last overhaul period (i is taken as cold, warm or hot starts); E si ——Convert a single start of a certain type (i) into effective utilization hours, that is, convert the damage caused by a single start into the damage caused by a specific effective utilization hours; C m ——the average annual maintenance cost of the last overhaul cycle, in yuan; C mps,i ——Maintenance cost per unit effective utilization hour, unit: RMB / h; C mph ——Single startup maintenance fee of a certain type, in yuan; C3——no-load maintenance cost per hour, in RMB; Step 4: Calculate the opportunity cost C4 caused by the increase in the equivalent forced outage rate Where: ——Average variable cost, unit: RMB / MWh; ——Average marginal cost per kilowatt-hour, unit: RMB / MWh; ——no-load cost per kilowatt-hour, unit: RMB / MWh; ——Average fuel consumption cost, unit: RMB / MWh; ——Average material consumption cost (including water, limestone, ammonia injection, etc.), unit: RMB / MWh; ——No-load fuel consumption cost per kilowatt-hour, unit: RMB / MWh; ——Maintenance cost per kilowatt-hour, unit: RMB / MWh; C3——no-load maintenance cost per hour, unit: RMB / h; F max ——Power supply fuel consumption of the unit at rated output, in t / h; F min ——Power supply fuel consumption of the unit at minimum technical output, in t / h; G max ——Rated capacity of the unit, in MW; G min ——Minimum technical output of the unit, in MW; H u ——the average effective utilization hours per year of the last overhaul cycle, in h; H r ——the average annual operating hours of the last overhaul cycle, in h; F nl ——no-load fuel consumption, unit: t / h; P cw ——standard coal price, unit: RMB / t; X EFOR ——The amount of EROR promoted by a single start; Step 5: Computer Group Fixed Cost C5 Where: C5——depreciation of fixed assets, in yuan; C jz ——Basic fixed investment cost per unit capacity, in RMB / MW; n——the service life of the unit, in years; η czl ——Estimated residual value rate of fixed assets, in %, calculated as 5%; Step 6: Determine the grid-connected price based on the power generation cost Combining steps 1 to 5, we can get the unit's power generation cost C, which includes the unit's fuel cost C1, startup cost, opportunity cost C4 caused by the increase in the equivalent forced outage rate, and fixed cost C5. Based on these various cost components, the cost-plus method is used to make a grid-connected quotation: Where: O——quote, yuan / kWh C——power generation cost, yuan / kWh Δ——target profit, yuan / kWh 1.13 - VAT rate, f – profit rate; The startup cost includes startup fuel consumption fee C2 and group startup related maintenance fee C3.

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