CN108691585B - Method for calculating low pressure cylinder efficiency of condensing steam turbine - Google Patents
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Abstract
A method for calculating the low pressure cylinder efficiency of a condensing steam turbine relates to the field of steam turbines and comprises the following steps: measuring thermodynamic system parameters; calculating the enthalpy value of the steam flow; obtaining the water supply flow; calculating the corrected steam leakage amount of the shaft seals; obtaining the ideal enthalpy drop of the low-pressure cylinder and the ideal enthalpy drop of the steam turbine; calculating the regenerative steam extraction amount of the high-pressure heater and the deaerator, calculating the flow rate of condensed water at the inlet of the deaerator, and calculating the regenerative steam extraction amount of the low-pressure heater; determining the acting loss of various shaft seal steam leakage and regenerative steam extraction; obtaining the efficiency of a high-pressure cylinder and the efficiency of a medium-pressure cylinder; calculating the actual internal power of the steam turbine, solving the ideal internal power of the steam turbine, and calculating the relative internal efficiency of the steam turbine; and obtaining the efficiency of the low pressure cylinder. The invention converts the low-pressure cylinder efficiency into the steam turbine ideal enthalpy drop and the steam turbine internal efficiency, reduces the measuring points required by the test, has simple calculation process and high precision, and can completely meet the engineering requirements.
Description
Technical Field
The invention relates to the field of steam turbines, in particular to a method for calculating the low pressure cylinder efficiency of a condensing steam turbine.
Background
The low pressure cylinder efficiency of the steam turbine is defined as the ratio of the actual enthalpy drop of the low pressure cylinder to the ideal enthalpy drop, in order to obtain the low pressure cylinder efficiency, the exhaust enthalpy of the low pressure cylinder must be measured, and the condensing steam turbine has no method for accurately measuring the exhaust humidity because the exhaust steam of the low pressure cylinder is in a wet steam area, so that the exhaust enthalpy of the low pressure cylinder cannot be directly determined. In order to obtain the efficiency of the low-pressure cylinder of the condensing steam turbine, according to the existing ASME PTC6-2004 steam turbine performance test regulation and GB/T8117.1-2008 steam turbine thermal performance acceptance test regulation, a complete steam turbine thermal performance test needs to be carried out, a large number of test points are replaced, then steam turbine mass balance and heat balance calculation are carried out, repeated iteration is carried out to obtain the exhaust enthalpy of the low-pressure cylinder, some auxiliary flows in a steam turbine thermal system cannot be accurately measured, and measurement errors objectively existing in a test instrument are finally accumulated in the iteration process, so that the calculation precision of the exhaust enthalpy of the low-pressure cylinder is inevitably influenced, and the calculation accuracy of the efficiency of the low-pressure cylinder is influenced.
Disclosure of Invention
The invention aims to solve the problems and provides a method for calculating the low-pressure cylinder efficiency of a condensing steam turbine, which is used for converting the low-pressure cylinder efficiency into the ideal enthalpy drop of the steam turbine and the relative internal efficiency of the steam turbine.
The technical scheme adopted by the invention for solving the technical problems is as follows:
a method for calculating the low pressure cylinder efficiency of a condensing steam turbine comprises the following steps:
measuring parameters of a turbine thermodynamic system, including pressure, temperature, flow and active power of a generator;
step (2), according to the water and steam property table, the enthalpy value of the steam-water flow is obtained;
step (3), according to the actually measured flow rate of condensed water at the inlet of the deaerator, calculating the water supply flow rate through the flow balance and the heat balance of a heat regeneration system;
step (4), respectively calculating the isentropic expansion lines of the high-pressure cylinder, the intermediate-pressure cylinder and the low-pressure cylinder, and calculating the corrected shaft seal steam leakage amount according to the shaft seal steam leakage amount and the relevant state of the steam expansion process;
step (5), according to the steam isentropic expansion line of each cylinder determined in the step (4), determining the enthalpy value of each regenerative steam extraction point by utilizing the actually measured intersection point of the steam extraction pressure of each cylinder and the isentropic expansion line, and determining the isentropic exhaust enthalpy of the low-pressure cylinder by utilizing the actually measured intersection point of the exhaust steam pressure of the low-pressure cylinder of the steam turbine and the isentropic expansion line of the medium-low pressure cylinder to obtain the ideal enthalpy drop of the low-pressure cylinder and the ideal enthalpy drop of the steam turbine;
step (6), according to the flow balance and the heat balance of the high-pressure heater, keeping the water supply flow determined in the step (3) unchanged, calculating the regenerative steam extraction amount of the high-pressure heater and the deaerator, calculating the converted deaerator inlet condensate flow, and then calculating the regenerative steam extraction amount of the low-pressure heater according to the flow balance and the heat balance of the low-pressure heater by taking the converted deaerator inlet condensate flow as a reference;
step (7), determining the work loss of the shaft seal steam leakage quantity and the regenerative steam extraction quantity in the steps (3) and (6);
step (8), respectively calculating the high-pressure cylinder efficiency and the medium-pressure cylinder efficiency of the steam turbine according to the ratio of the actual enthalpy drop to the ideal enthalpy drop;
step (9), calculating the actual internal power of the steam turbine according to the active power of the generator, the efficiency of the generator and the mechanical loss of the steam turbine, then obtaining the ideal internal power of the steam turbine according to the work loss determined in the steps (7) to (8) and the ideal enthalpy drop of the steam turbine, and calculating the relative internal efficiency of the steam turbine;
and (10) calculating the efficiency of the low-pressure cylinder according to the ideal enthalpy drop of the steam turbine, the actual internal power of the steam turbine, the ideal internal power of the steam turbine, the internal efficiency of the steam turbine, the ideal enthalpy drop of the high-pressure cylinder, the efficiency of the high-pressure cylinder, the ideal enthalpy drop of the intermediate-pressure cylinder and the efficiency of the intermediate-pressure cylinder obtained in the step (8) and the step (9) and the ideal enthalpy drop of the low-pressure cylinder determined in the step (5).
Further, in the step (1),
the pressure comprises main steam pressure, reheating pressure, high discharge pressure, middle discharge pressure, low-pressure cylinder discharge pressure, pressure of each steam extraction port, steam inlet pressure of each heater, condensation water pressure and water supply pressure;
the temperature comprises main steam temperature, reheating temperature, high exhaust temperature, middle exhaust temperature, temperature of each steam extraction port and temperature of each heater (steam inlet, water outlet and drainage);
the flow comprises the flow of condensate at the inlet of the deaerator and the steam leakage of each shaft seal.
Further, in the step (4), when the shaft seal steam leakage amount is not related to the steam expansion process, namely, the steam leakage occurs before the steam enters the steam turbine for expansion, the steam leakage amount is an actual measured value or a design value;
when the shaft seal steam leakage quantity is related to the steam expansion process, the steam leakage quantity under the isentropic expansion state needs to be corrected, and the correction calculation formula of the steam leakage quantity is as follows:
in formula (II), G'gThe leakage of steam from the shaft seal in the isentropic expansion state, GgIs measured or designed shaft seal steam leakage quantity v'gIs the specific volume v of shaft seal leakage in the isentropic expansion stategThe specific volume of the shaft seal leakage is measured or designed.
Further, in the step (4), the isentropism in the isentropic expansion line of the high-pressure cylinder means that the main steam entropy is kept unchanged during the expansion process of the steam in the high-pressure cylinder; the isentropic in the isentropic expansion line of the medium-low pressure cylinder means that the reheating entropy is kept constant.
Further, in the step (5), the calculation formula of the ideal enthalpy drop of the low-pressure cylinder is as follows: Δ HtL＝HeM-HtcLIn the formula,. DELTA.HtLIs an ideal enthalpy drop of the low pressure cylinder, HeMIs the exhaust enthalpy of the intermediate pressure cylinder HtcLThe constant entropy exhaust enthalpy of the low pressure cylinder; the calculation formula of the ideal enthalpy drop of the steam turbine is as follows: Δ Ht＝H0-HthH+Hrh-HtcLIn the formula,. DELTA.HtIs an ideal enthalpy drop, H, of the steam turbine0Is the enthalpy of the main steam, HthHIs high in isentropic enthalpy, HrhIs the reheat enthalpy, HtcLIs the low-pressure cylinder exhaust isentropic enthalpy.
Further, in the step (7), the shaft seal leakage steam volume and the regenerative steam extraction volume are divided into two types by taking the reheat steam point as a boundary: one type is before the reheat and the other type is after the reheat.
Further, in the step (7), the work loss calculation formula of the shaft seal steam leakage amount and the regenerative steam extraction amount before reheating is as follows: i isc1＝(Hc1-HthH+Hr-HtcL)×Gc1In the formula, Ic1Work loss for shaft seal leakage or regenerative extraction before reheating, Hc1Is the isentropic enthalpy, H, of shaft seal steam leakage or backheating steam extraction in the isentropic expansion statethHIs high in isentropic enthalpy, HrIs the reheat enthalpy, HtcLIsentropic enthalpy of low-pressure cylinder exhaust, Gc1The shaft seal leakage steam quantity or the backheating steam extraction quantity in the isentropic expansion state;
the working loss calculation formula of the shaft seal steam leakage amount and the regenerative steam extraction amount after reheating is as follows: i isc2＝(Hc2-HtcL)×Gc2In the formula, Ic2Work loss for shaft seal leakage or regenerative extraction after reheating, Hc2Is the isentropic enthalpy, H, of shaft seal steam leakage or backheating steam extraction in the isentropic expansion statetcLIsentropic enthalpy of low-pressure cylinder exhaust, Gc2The steam leakage quantity of the shaft seal or the backheating steam extraction quantity in the isentropic expansion state.
Further, in the step (9), the calculation formula of the actual internal power of the steam turbine is as follows: pi＝Pg/ηg+ΔPmIn the formula, PiFor actual internal power of the turbine, PgFor active power of the generator, ηgTaking the design value, Δ P, for the efficiency of the generatormTaking a design value for the mechanical loss of the steam turbine;
the calculation formula of the ideal internal power of the steam turbine is as follows: pt＝G0·ΔHt-∑IcIn the formula, PtFor ideal internal power of steam turbines, G0Main steam flow, Δ HtFor ideal enthalpy drop of steam turbine, ∑ IcThe sum of all work loss obtained in the step (7);
the calculation formula of the relative efficiency of the steam turbine is ηp＝Pi/PtIn the formula, ηpThe relative internal efficiency of the turbine is obtained.
Further, in the step (10), the calculation formula of the low cylinder efficiency is ηL＝(ΔHt·ηp-ΔHtH·ηH-ΔHtM·ηM)/ΔHtLIn the formula ηLFor low cylinder efficiency, Δ HtFor ideal enthalpy drop of steam turbine, ηpFor the relative internal efficiency of the turbine, Δ HtHη for ideal enthalpy drop of high-pressure cylinderHFor high cylinder efficiency, Δ HtMη for ideal enthalpy drop of intermediate pressure cylinderMFor efficiency of the intermediate cylinder, Δ HtLIs an ideal enthalpy drop of the low-pressure cylinder.
The invention has the beneficial effects that:
the low-pressure cylinder efficiency calculation method is used for solving the low-pressure cylinder efficiency by looking at the whole turbine thermodynamic system from the power perspective and converting the low-pressure cylinder efficiency into the ideal enthalpy drop of the turbine and the relative internal efficiency of the turbine, and the low-pressure cylinder exhaust enthalpy is solved by adopting an isentropic expansion line instead of iterative calculation, so that measuring points required by tests are greatly reduced, the calculation process is simple, the calculation result precision is high, and the engineering requirements can be completely met.
Drawings
FIG. 1 is a schematic diagram of a system architecture and measurement calculation.
Detailed Description
As shown in fig. 1, the condensing steam turbine at least includes a high and medium pressure cylinder, a heat recovery system, a reheating system, a condensing steam system, and the like, and a method for calculating the efficiency of the low pressure cylinder of the condensing steam turbine includes the following steps:
step (1)
Respectively measuring parameters of a turbine thermodynamic system, including pressure, temperature, flow and active power of a generator;
the pressure comprises main steam pressure, reheating pressure, high discharge pressure, middle discharge pressure, low-pressure cylinder discharge pressure, pressure of each steam extraction port, steam inlet pressure of each heater, condensation water pressure and water supply pressure;
the temperature comprises main steam temperature, reheating temperature, high exhaust temperature, middle exhaust temperature, temperature of each steam extraction port and temperature of each heater (steam inlet, water outlet and drainage);
the flow comprises the flow of condensate at the inlet of the deaerator and the steam leakage of each shaft seal.
Step (2)
And (4) according to the water and steam property table, obtaining the enthalpy value of the steam-water flow.
Step (3)
And (4) according to the actually measured flow of condensed water at the inlet of the deaerator, calculating the water supply flow through the flow balance and the heat balance of a heat regeneration system.
Step (4)
Respectively calculating the isentropic expansion lines of the high-pressure cylinder and the medium-low pressure cylinder, and calculating the corrected shaft seal steam leakage quantity according to the shaft seal steam leakage quantity and the relevant state of the steam expansion process;
the isentropic in the isentropic expansion line of the high-pressure cylinder means that the main steam entropy is kept unchanged in the expansion process of steam in the high-pressure cylinder; the isentropic of the low-and-medium-pressure cylinder isentropic expansion line means that the reheat entropy is kept unchanged, and the medium-and-medium-pressure isentropic expansion line is the same line because the medium-row state point is superposed with the steam inlet state point of the low-pressure cylinder, the starting point of the expansion line is reheat, and the end point of the expansion line is low-pressure cylinder steam discharge.
In the step (4), the shaft seal steam leakage amount is irrelevant to the steam expansion process, namely, the steam leakage occurs before the steam enters the steam turbine for expansion, such as high and medium pressure gate rod shaft seal steam leakage and high pressure cylinder front shaft seal steam leakage, and the steam leakage amount is an actual measurement value or a design value without correction;
the shaft seal steam leakage quantity is related to the steam expansion process, if the high pressure cylinder rear shaft seal steam leakage and the intermediate pressure cylinder rear shaft seal steam leakage need to be corrected to the steam leakage quantity in the isentropic expansion state, and the correction calculation formula of the steam leakage quantity is as follows:
in formula (II), G'gThe leakage of steam from the shaft seal in the isentropic expansion state, GgIs measured or designed shaft seal steam leakage quantity v'gIs the specific volume v of shaft seal leakage in the isentropic expansion stategThe specific volume of the shaft seal leakage is measured or designed.
Step (5)
According to the steam isentropic expansion line of each cylinder determined in the step (4), determining the enthalpy value of each regenerative steam extraction point by utilizing the actually measured intersection point of the steam extraction pressure of each cylinder and the isentropic expansion line, determining the isentropic exhaust enthalpy of the low-pressure cylinder by utilizing the actually measured intersection point of the exhaust pressure of the low-pressure cylinder of the steam turbine and the isentropic expansion line of the medium-low pressure cylinder, and solving the ideal enthalpy drop of the low-pressure cylinder and the ideal enthalpy drop of the steam turbine;
the calculation formula of the ideal enthalpy drop of the low-pressure cylinder is as follows: Δ HtL＝HeM-HctLIn the formula,. DELTA.HtLIs an ideal enthalpy drop of the low pressure cylinder, HeMIs the exhaust enthalpy of the intermediate pressure cylinder HtcLThe constant entropy exhaust enthalpy of the low pressure cylinder; the calculation formula of the ideal enthalpy drop of the steam turbine is as follows: Δ Ht＝H0-HthH+Hrh-HtcLIn the formula,. DELTA.HtIs an ideal enthalpy drop, H, of the steam turbine0Is the enthalpy of the main steam, HthHIs high in isentropic enthalpy, HrhIs the reheat enthalpy, HtcLIs the low-pressure cylinder exhaust isentropic enthalpy.
Step (6)
And (4) according to the flow balance and the heat balance of the high-pressure heater, keeping the water supply flow determined in the step (3) unchanged, calculating the regenerative steam extraction amount of the high-pressure heater and the deaerator, and calculating the converted deaerator inlet condensate flow. Calculating the regenerative steam extraction quantity of the low-pressure heater according to the flow balance and the heat balance of the low-pressure heater by taking the converted deaerator inlet condensed water flow as a reference;
step (7)
Determining the work loss of the shaft seal steam leakage quantity and the backheating steam extraction quantity in the steps (3) and (6);
the shaft seal leakage steam volume and the regenerative extraction steam volume of various types take a reheat steam point as a boundary: one is before the reheat and the other is after the reheat;
the work loss calculation method of the shaft seal steam leakage amount and the regenerative steam extraction amount before reheating has the following calculation formula: i isc1＝(Hc1-HthH+Hr-HtcL)×Gc1In the formula, Ic1Work loss for shaft seal leakage or regenerative extraction before reheating, Hc1Is the isentropic enthalpy, H, of shaft seal steam leakage or backheating steam extraction in the isentropic expansion statethHIs high in isentropic enthalpy, HrIs the reheat enthalpy, HtcLIsentropic enthalpy of low-pressure cylinder exhaust, Gc1The shaft seal leakage steam quantity or the backheating steam extraction quantity in the isentropic expansion state;
the working loss calculation formula of the shaft seal steam leakage amount and the regenerative steam extraction amount after reheating is as follows: i isc2＝(Hc2-HtcL)×Gc2In the formula, Ic2Work loss for shaft seal leakage or regenerative extraction after reheating, Hc2Is the isentropic enthalpy, H, of shaft seal steam leakage or backheating steam extraction in the isentropic expansion statetcLIsentropic enthalpy of low-pressure cylinder exhaust, Gc2The steam leakage quantity of the shaft seal or the backheating steam extraction quantity in the isentropic expansion state.
Step (8)
And respectively calculating the high-pressure cylinder efficiency and the medium-pressure cylinder efficiency of the steam turbine according to the ratio of the actual enthalpy drop to the ideal enthalpy drop.
Step (9)
Calculating the actual internal power of the steam turbine according to the active power of the generator, the efficiency of the generator and the mechanical loss of the steam turbine, solving the ideal internal power of the steam turbine according to the work loss determined in the steps (7) to (8) and the ideal enthalpy drop of the steam turbine, and calculating the internal efficiency of the steam turbine;
the calculation formula of the actual internal power of the steam turbine is as follows: pi＝Pg/ηg+ΔPmIn the formula, PiFor actual internal power of the turbine, PgFor active power of the generator, ηgTaking the design value, Δ P, for the efficiency of the generatormTaking a design value for the mechanical loss of the steam turbine;
the calculation formula of the ideal internal power of the steam turbine is as follows: pt＝G0·ΔHt-∑IcIn the formula, PtFor ideal internal power of steam turbines, G0Main steam flow, Δ HtFor ideal enthalpy drop of steam turbine, ∑ IcThe sum of all work loss obtained in the step (7);
the calculation formula of the relative efficiency of the steam turbine is ηp＝Pi/PtIn the formula, ηpThe relative internal efficiency of the turbine is obtained.
Step (10)
And (4) obtaining the efficiency of the low pressure cylinder according to the ideal enthalpy drop of the steam turbine, the actual internal power of the steam turbine, the ideal internal power of the steam turbine, the internal efficiency of the steam turbine, the ideal enthalpy drop of the high pressure cylinder, the efficiency of the high pressure cylinder, the ideal enthalpy drop of the intermediate pressure cylinder and the efficiency of the intermediate pressure cylinder obtained in the step (8) and the step (9) and the ideal enthalpy drop of the low pressure cylinder determined in the step (5).
The calculation formula of the low pressure cylinder efficiency is ηL＝(ΔHt·ηp-ΔHtH·ηH-ΔHtM·ηM)/ΔHtLIn the formula ηLFor low cylinder efficiency, Δ HtFor ideal enthalpy drop of steam turbine, ηpFor the relative internal efficiency of the turbine, Δ HtHη for ideal enthalpy drop of high-pressure cylinderHFor high cylinder efficiency, Δ HtMη for ideal enthalpy drop of intermediate pressure cylinderMFor efficiency of the intermediate cylinder, Δ HtLIs an ideal enthalpy drop of the low-pressure cylinder.
Application example: taking an N1013-28/600/620 type condensing steam turbine of a certain plant as an example, the method of the invention is used for calculating the efficiency of the low-pressure cylinder, and the calculation result is shown in the following table.
In addition to the technical features described in the specification, the technology is known to those skilled in the art.
Claims (9)
1. A method for calculating the low pressure cylinder efficiency of a condensing steam turbine is characterized by comprising the following steps:
measuring parameters of a turbine thermodynamic system, including pressure, temperature, flow and active power of a generator;
step (2), according to the water and steam property table, the enthalpy value of the steam-water flow is obtained;
step (3), according to the actually measured flow rate of condensed water at the inlet of the deaerator, calculating the water supply flow rate through the flow balance and the heat balance of a heat regeneration system;
step (4), respectively calculating the isentropic expansion lines of the high-pressure cylinder, the intermediate-pressure cylinder and the low-pressure cylinder, and calculating the corrected shaft seal steam leakage amount according to the shaft seal steam leakage amount and the relevant state of the steam expansion process;
step (5), according to the steam isentropic expansion line of each cylinder determined in the step (4), determining the enthalpy value of each regenerative steam extraction point by utilizing the actually measured intersection point of the steam extraction pressure of each cylinder and the isentropic expansion line, and determining the isentropic exhaust enthalpy of the low-pressure cylinder by utilizing the actually measured intersection point of the exhaust steam pressure of the low-pressure cylinder of the steam turbine and the isentropic expansion line of the medium-low pressure cylinder to obtain the ideal enthalpy drop of the low-pressure cylinder and the ideal enthalpy drop of the steam turbine;
step (6), according to the flow balance and the heat balance of the high-pressure heater, keeping the water supply flow determined in the step (3) unchanged, calculating the regenerative steam extraction amount of the high-pressure heater and the deaerator, calculating the converted deaerator inlet condensate flow, and then calculating the regenerative steam extraction amount of the low-pressure heater according to the flow balance and the heat balance of the low-pressure heater by taking the converted deaerator inlet condensate flow as a reference;
step (7), determining the work loss of the shaft seal steam leakage quantity and the regenerative steam extraction quantity in the steps (3) and (6);
step (8), respectively calculating the high-pressure cylinder efficiency and the medium-pressure cylinder efficiency of the steam turbine according to the ratio of the actual enthalpy drop to the ideal enthalpy drop;
step (9), calculating the actual internal power of the steam turbine according to the active power of the generator, the efficiency of the generator and the mechanical loss of the steam turbine, then obtaining the ideal internal power of the steam turbine according to the work loss determined in the steps (7) to (8) and the ideal enthalpy drop of the steam turbine, and calculating the relative internal efficiency of the steam turbine;
and (10) calculating the efficiency of the low-pressure cylinder according to the ideal enthalpy drop of the steam turbine, the actual internal power of the steam turbine, the ideal internal power of the steam turbine, the internal efficiency of the steam turbine, the ideal enthalpy drop of the high-pressure cylinder, the efficiency of the high-pressure cylinder, the ideal enthalpy drop of the intermediate-pressure cylinder and the efficiency of the intermediate-pressure cylinder obtained in the step (8) and the step (9) and the ideal enthalpy drop of the low-pressure cylinder determined in the step (5).
2. The method for calculating the low cylinder efficiency of a condensing steam turbine according to claim 1, wherein in said step (1),
the pressure comprises main steam pressure, reheating pressure, high discharge pressure, middle discharge pressure, low-pressure cylinder discharge pressure, pressure of each steam extraction port, steam inlet pressure of each heater, condensation water pressure and water supply pressure;
the temperature comprises main steam temperature, reheating temperature, high exhaust temperature, middle exhaust temperature, temperature of each steam extraction port and temperature of each heater;
the flow comprises the flow of condensate at the inlet of the deaerator and the steam leakage of each shaft seal.
3. The method for calculating the efficiency of the condensing steam turbine low-pressure cylinder according to claim 1, wherein in the step (4), when the shaft seal leakage is not related to the steam expansion process, i.e. the leakage occurs before the steam enters the steam turbine to expand, the leakage is an actual measured value or a designed value;
when the shaft seal steam leakage quantity is related to the steam expansion process, the steam leakage quantity under the isentropic expansion state needs to be corrected, and the correction calculation formula of the steam leakage quantity is as follows:
in formula (II), G'gThe leakage of steam from the shaft seal in the isentropic expansion state, GgIs measured or designed shaft seal steam leakage quantity v'gIs the specific volume v of shaft seal leakage in the isentropic expansion stategThe specific volume of the shaft seal leakage is measured or designed.
4. The method for calculating the low-pressure cylinder efficiency of the condensing steam turbine as claimed in claim 1, wherein in the step (4), the isentropism in the isentropic expansion line of the high-pressure cylinder means that the main steam entropy is kept unchanged during the expansion of the steam in the high-pressure cylinder; the isentropic in the isentropic expansion line of the medium-low pressure cylinder means that the reheating entropy is kept constant.
5. The method for calculating the low-pressure cylinder efficiency of a condensing steam turbine according to claim 1, wherein in the step (5), the ideal enthalpy drop of the low-pressure cylinder is calculated by the formula: Δ HtL＝HeM-HtcLIn the formula,. DELTA.HtLIs an ideal enthalpy drop of the low pressure cylinder, HeMIs the exhaust enthalpy of the intermediate pressure cylinder HtcLThe constant entropy exhaust enthalpy of the low pressure cylinder; the calculation formula of the ideal enthalpy drop of the steam turbine is as follows: Δ Ht＝H0-HthH+Hrh-HtcLIn the formula,. DELTA.HtIs an ideal enthalpy drop, H, of the steam turbine0Is the enthalpy of the main steam, HthHIs high in isentropic enthalpy, HrhIs the reheat enthalpy, HtcLIs the low-pressure cylinder exhaust isentropic enthalpy.
6. The method for calculating the efficiency of the low-pressure cylinder of the condensing steam turbine as claimed in claim 1, wherein in the step (7), the shaft seal leakage steam volume and the regenerative extraction steam volume are divided into two types by taking the reheat steam point as a boundary: one type is before the reheat and the other type is after the reheat.
7. The method for calculating the efficiency of the low-pressure cylinder of the condensing steam turbine according to claim 1, wherein in the step (7), the work loss calculation formulas of the shaft seal leakage steam quantity and the regenerative extraction steam quantity before reheating are as follows: i isc1＝(Hc1-HthH+Hr-HtcL)×Gc1In the formula, Ic1Work loss for shaft seal leakage or regenerative extraction before reheating, Hc1Is the isentropic enthalpy, H, of shaft seal steam leakage or backheating steam extraction in the isentropic expansion statethHIs high in isentropic enthalpy, HrIs the reheat enthalpy, HtcLIsentropic enthalpy of low-pressure cylinder exhaust, Gc1The shaft seal leakage steam quantity or the backheating steam extraction quantity in the isentropic expansion state;
shaft seal leakage and return after reheatingThe working loss calculation formula of the hot steam extraction amount is as follows: i isc2＝(Hc2-HtcL)×Gc2In the formula, Ic2Work loss for shaft seal leakage or regenerative extraction after reheating, Hc2Is the isentropic enthalpy, H, of shaft seal steam leakage or backheating steam extraction in the isentropic expansion statetcLIsentropic enthalpy of low-pressure cylinder exhaust, Gc2The steam leakage quantity of the shaft seal or the backheating steam extraction quantity in the isentropic expansion state.
8. The method for calculating the low cylinder efficiency of a condensing steam turbine according to claim 1, wherein in the step (9), the actual internal power of the turbine is calculated by the formula: pi＝Pg/ηg+ΔPmIn the formula, PiFor actual internal power of the turbine, PgFor active power of the generator, ηgTaking the design value, Δ P, for the efficiency of the generatormTaking a design value for the mechanical loss of the steam turbine;
the calculation formula of the ideal internal power of the steam turbine is as follows: pt＝G0·ΔHt-∑IcIn the formula, PtFor ideal internal power of steam turbines, G0Main steam flow, Δ HtFor ideal enthalpy drop of steam turbine, ∑ IcThe sum of all work loss obtained in the step (7);
the calculation formula of the relative efficiency of the steam turbine is ηp＝Pi/PtIn the formula, ηpThe relative internal efficiency of the turbine is obtained.
9. The method for calculating the low pressure cylinder efficiency of a condensing steam turbine according to claim 1, wherein in the step (10), the low pressure cylinder efficiency is calculated by ηL＝(ΔHt·ηp-ΔHtH·ηH-ΔHtM·ηM)/ΔHtLIn the formula ηLFor low cylinder efficiency, Δ HtFor ideal enthalpy drop of steam turbine, ηpFor the relative internal efficiency of the turbine, Δ HtHη for ideal enthalpy drop of high-pressure cylinderHFor high cylinder efficiency, Δ HtMIs composed ofIdeal enthalpy drop of cylinder, ηMFor efficiency of the intermediate cylinder, Δ HtLIs an ideal enthalpy drop of the low-pressure cylinder.
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| CN109489098A (en) * | 2018-11-22 | 2019-03-19 | 李申强 | A kind of circulating water heating system for large-scale Condensing steam turine |
| CN111622814B (en) * | 2020-06-05 | 2024-05-28 | 浙江浙能技术研究院有限公司 | Method and system for controlling energy-saving operation of low-pressure cylinder of steam turbine based on real-time online operation data |
| CN112100751B (en) * | 2020-07-29 | 2023-09-08 | 国网山东省电力公司电力科学研究院 | Method and system for calculating influence of back pressure change of extraction condensing unit on unit power |
| CN112666388B (en) * | 2020-12-15 | 2023-01-24 | 广西电网有限责任公司电力科学研究院 | Device for acquiring electric power range by heat supply flow |
| CN113076632B (en) * | 2021-03-24 | 2024-01-12 | 中冶华天工程技术有限公司 | Steam turbine exhaust enthalpy soft measurement method for saturated steam generator set |
| CN113486472B (en) * | 2021-07-26 | 2024-04-26 | 国能南京电力试验研究有限公司 | Method for calculating influence of steam turbine cylinder efficiency on heat consumption rate |
| CN113982709B (en) * | 2021-11-08 | 2023-08-01 | 国家能源集团内蒙古电力有限公司 | Method and device for calculating instantaneous heat supply steam extraction amount of steam turbine and electronic equipment |
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