A method for calculating the balance degree of power system in power plants

Abstract

The present invention provides a method for calculating the balance of a power plant power system, and relates to the technical field of power systems. The method first analyzes the influence of the two-to-one and one-to-one operation modes of a gas-steam combined cycle unit on the balance of the power plant, and calculates the influence factors of the two operation modes of the gas-steam combined cycle unit on the balance of the power plant; then, the power balance of the high-voltage power distribution system and the low-voltage power distribution system are calculated respectively; finally, the influence of any power equipment on the balance of the power plant is analyzed, and on the basis of the power balance calculation method of the high-voltage power distribution system and the low-voltage power distribution system, the contribution of the power equipment to the balance of the power plant system is calculated. The method can be used to calculate the balance of the high-voltage power distribution system and the low-voltage power distribution system, and at the same time, the influence of the equipment itself on the balance of the power plant can be determined by the change of the balance of the power plant system before and after the start of any power equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a method for calculating the balance of a power system of a power plant. Background Art

[0002] With the development of economy and society, my country's electricity demand is increasing, and the requirements for safe and stable operation of power system are getting higher and higher. Stable power transmission of power plants is a prerequisite for ensuring the stability of power system. Therefore, the balance of power supply is very important for stable power transmission of power plants. It is very important to calculate the balance of power supply and master the balance state of power supply. In order to solve the above problems, a method for calculating the balance of power supply is needed to calculate the balance value of power supply and the contribution of power supply equipment to the balance of power supply, and determine the balance state of power supply system. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for calculating the balance of a power plant's power system in response to the above-mentioned deficiencies in the prior art, calculate the power balance value and the contribution of power equipment to the power balance, and determine the balance state of the power system.

[0004] In order to solve the above technical problems, the technical scheme adopted by the present invention is: a method for calculating the balance of the power system of a power plant, firstly analyzing the influence of the two-to-one operation mode of the gas-steam combined cycle unit on the balance of the power system and the influence of the one-to-one operation mode on the balance of the power system, and calculating the influence factors of the two-to-one and one-to-one operation modes of the gas-steam combined cycle unit on the balance of the power system; then, respectively calculating the power balance of the high-voltage power distribution system (6kV system) and the low-voltage power distribution system (380V system); finally, analyzing the influence of any power equipment on the balance of the power system, and calculating the contribution of the power equipment to the balance of the power system on the basis of the above-mentioned 6kV system and 380V system power balance calculation methods, specifically including the following steps:

[0005] Step 1: Calculate the impact factors of the two-on-one and one-on-one operation modes of the gas-steam combined cycle units on the balance of plant power consumption;

[0006] Step 1.1: Collect the historical voltage U of the plant high-voltage distribution system when n gas-steam combined cycle units adopt the two-to-one operation mode i0 、Current I i0 , Power P i0 , Power Factor When n and n groups adopt one-to-one operation mode, the historical voltage U of the plant high-voltage distribution system i1 、Current I i1 , Power P i1 , Power Factor

[0007] Step 1.2: Calculate the per-unit value of the data collected in step 1.1, as shown in the following formula:

[0008]

[0009]

[0010] Among them, U i0,b and U′ i0 The voltage U i0 The reference value and per unit value, I i0,b and I′ i0 The current I i0 The reference value and per unit value, P i0,b and P′ i0 The power P i0 The reference value and per unit value of and The power factor The reference value and per unit value, U i1,b and U′ i1 The voltage U i1 The reference value and per unit value, I i1,b and I′ i1 The current I i1 The reference value and per unit value, P i1，b and P′ i1 The power P i1 The reference value and per unit value of and The power factor The reference value and per unit value of

[0011] Step 1.3: Calculate the impact factors of the two-on-one and one-on-one operation modes of the gas-steam combined cycle units on the balance of plant power consumption;

[0012] The influence factor φ0 of the two-to-one operation mode of the gas-steam combined cycle unit on the balance of plant power consumption is shown in the following formula:

[0013]

[0014] The influence factor of one-to-one operation mode of gas-steam combined cycle units on the balance of power consumption of the power plant t As shown in the following formula:

[0015]

[0016] Step 2: Calculate the power balance of the plant's high-voltage power distribution system;

[0017] Step 2.1: Collect the real-time voltage U of the high-voltage power distribution system used in the factoryh 、Current I h , power P h , Power Factor The data are then used to calculate the per unit value, as shown in the following formula:

[0018]

[0019] Among them, U hL,b and U h ′ are voltage U h The reference value and per unit value, I h,b and I h ′ are the current I h The reference value and per unit value, P h,b and P h ′ are power P h The reference value and per unit value of and The power factor The reference value and per unit value of

[0020] Step 2.2: Calculate the power balance degree δ0 of the plant high-voltage power distribution system based on the data collected in step 2.1, as shown in the following formula:

[0021]

[0022] Step 3: Calculate the power balance of the factory's low-voltage power distribution system;

[0023] Step 3.1: Collect the real-time voltage U of the low-voltage power distribution system used in the factory l 、Current I l , power P l , Power Factor The data are then used to calculate the per unit value, as shown in the following formula:

[0024]

[0025] Among them, U l,b and U l ′ are voltage U l The reference value and per unit value, I l,b and I l ′ are the current I l The reference value and per unit value, P l,b and P l ′ are power P l The reference value and per unit value of and The power factor The reference value and per unit value of

[0026] Step 3.2: Calculate the power balance of the low-voltage power distribution system for the factory based on the data collected in step 3.1 t , as shown in the following formula:

[0027]

[0028] Step 4: Calculate the contribution of plant power equipment to the plant power balance;

[0029] Step 4.1: Calculate the power balance of the high-voltage power distribution system and the power balance of the low-voltage power distribution system before and after the power equipment is started;

[0030] Collect the voltage U of the high-voltage power distribution system before the power equipment is started h0 、Current I h0 , power P h0 , Power Factor Voltage U of the low voltage power distribution system for the factory l0 、Current I l0 , power P l0 , Power Factor The voltage U of the high-voltage power distribution system after the power equipment is started h1 、Current I h1 , power P h1 , Power Factor System voltage U of the factory low-voltage power distribution system l1 、Current I l1 , power P l1 , Power Factor According to the calculation method of the system power balance in step 2 and step 3, the power balance of the high-voltage power distribution system before and after the power equipment is started is calculated, δ0 and δ 01 And the power balance degree of the low-voltage power distribution system used in the factory δ t , δ t1 ;

[0031] Step 4.2: Calculate the contribution of plant power equipment to the plant power balance;

[0032] Calculate the contribution of plant power equipment to the plant power balance as shown in the following formula:

[0033]

[0034] The beneficial effect of adopting the above technical scheme is that: the method for calculating the balance of the power system of a power plant provided by the present invention solves the problem that the previous method for calculating the balance of the power system can generally only be applied to the balance calculation of the power distribution system of 10kV and above, and can be used to calculate the balance of 6kV and 380V distribution systems. At the same time, the change in the balance of the power system before and after the startup of any power-consuming equipment can determine the degree of influence of the equipment itself on the balance of the power system, so as to better grasp the balance state of the power system in real time. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A flow chart of a method for calculating the balance degree of a power plant power system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0037] This embodiment takes a thermal power plant in a certain region as an example, and uses the power plant power system balance calculation method of the present invention to calculate the balance of the power plant power system, and at the same time, determines the degree of influence of the power equipment on the power balance.

[0038] In this embodiment, a method for calculating the balance degree of a power plant power system is provided. Figure 1 As shown, the following steps are included:

[0039] Step 1: Calculate the impact factors of the two-on-one and one-on-one operation modes of the gas-steam combined cycle units on the balance of plant power consumption;

[0040] The two-on-one gas-steam combined cycle unit has two operating modes: two-on-one and one-on-one. The change of operating mode affects the external power of the unit and the judgment of the power balance of the whole plant. Therefore, the impact of different operating modes on the power balance of the plant is analyzed first;

[0041] Step 1.1: Collect the historical voltage U of the plant high-voltage power distribution system (6KV system) when n gas-steam combined cycle units adopt the two-to-one operation mode i0 、Current I i0 , Power P i0 , Power Factor When n and n groups adopt one-to-one operation mode, the historical voltage U of the plant high-voltage distribution system i1 、Current I i1 , Power P i1 , Power Factor

[0042] In this embodiment, firstly, the historical influencing parameters of 10 groups of gas-steam combined cycle units are collected for the thermal power plants in the region. The historical voltage of the 6kV system when the gas-steam combined cycle units adopt the two-to-one operation mode, U 10 =5.96kV, U 20 =5.99kV, U 30 =6.02kV, U 40 =5.95kV, U 50 =5.98kV, U 60 =6.03kV, U 70 =5.97kV, U 80 =6.01kV, U 90 =6.09kV, U 100 =6.07kV, voltage reference value is 6kV; current I 10 =1867.2A,I 20 =1866.9A, I 30 =1866.7A, I 40 =1868.1A,I 50 =1867.3A,I 60 =1866.8A, I 70 =1867.9A, I 80 =1866.7A, I 90 =1866.5A, I 100 =1866.6A, current reference value 1867A; power P 10 =11.13MW, P 20 =11.18MW, P 30 =11.24MW, P 40 =11.12MW, P 50 =11.17MW, P 60 =11.27MW, P 70 =11.15MW, P 80 =11.22MW, P 90 =11.37MW, P 100 =11.33MW, power base value 11.2MW; power factor The power factor reference value is 0.8. When one-to-one operation is adopted, the system voltage is 6kV, U 11 =5.97kV, U 21 =5.99kV, U 31 =6.03kV, U 41 =5.97kV, U 51 =5.99kV, U 61 =6.02kV, U 71=5.96kV, U 81 =6.02kV, U 91 =6.05kV, U 101 =6.07kV, voltage reference value 6kV; current I 11 =696.7A, I 21 =696.9A, I 31 =697.1A, I 41 =696.6A, I 51 =696.8A, I 61 =697.1A, I 71 =697.2A, I 81 =696.8A, I 91 =696.7A, I 101 =697.1A, current reference value 697A; power P 11 =4.159MW, P 21 =4.174MW, P 31 =4.204MW, P 41 =4.159MW, P 51 =4.174MW, P 61 =4.197MW, P 71 =4.155MW, P 81 =4.195MW, P 91 =4.215MW, P 101 =4.231MW, power base value 4.2MW; The power factor reference value is 0.8.

[0043] Step 1.2: Calculate the per unit value of the data collected in step 1.1;

[0044] U' 10 =0.9933, U' 20 =0.9983, U' 30 =1.0033, U' 40 =0.9917, U' 50 =0.9967, U' 60 =1.005, U' 70 =0.995, U' 80 =1.0017, U' 90 =1.015, U' 100 =1.0117; I' 10 =1.0001, I' 20 =0.9999, I' 30 =0.9998, I' 40 =1.0006, I'50 =1.0002,I’ 60 =0.9999,I’ 70 =1.0005,I’ 80 =0.9999,I’ 90 =0.9997,I’ 100 =0.9998;P’ 10 =0.99375,P’ 20 =0.9982,P’ 30 =1.0036,P’ 40 =0.9929,P’ 50 =0.9973,P’ 60 =1.00625,P’ 70 =0.9955,P’ 80 =1.0018,P’ 90 =1.0152,P’ 100 =1.0116; U’ 11 =0.995,U’ 21 =0.9983,U’ 31 =1.005,U’ 41 =0.995,U’ 51 =0.9983,U’ 61 =1.0033,U’ 71 =0.9933,U’ 81 =1.0033,U’ 91 =1.0083,U’ 101 =1.0117;I’ 11 =0.9997,I’ 21 =0.9999,I’ 31 =1.0001,I’ 41 =0.9994,I’ 51 =0.9997,I’ 61 =1.0001,I’ 71 =1.0003,I’ 81 =0.9997,I’ 91 =0.9996,I’ 101 =1.0001;P’ 11 =0.9902,P’ 21 =0.9938,P’ 31 =1.0010,P’ 41 =0.9902,P’ 51 =0.9938,P’ 61 =0.9993,P’ 71=0.9893, P' 81 =0.9988, P' 91 =1.0036, P' 101 =1.0074;

[0045] Step 1.3: Calculate the impact factors of the two-on-one and one-on-one operation modes of the gas-steam combined cycle units on the balance of plant power consumption;

[0046] The influence factor φ0 of the two-to-one operation mode of the gas-steam combined cycle unit on the balance of plant power consumption is shown in the following formula:

[0047]

[0048] In this embodiment, φ0=1.246349394;

[0049] The influence factor of one-to-one operation mode of gas-steam combined cycle units on the balance of power consumption of the power plant t As shown in the following formula:

[0050]

[0051] In this embodiment, φ t =1.245048658;

[0052] Step 2: Calculate the power balance of the plant high-voltage power distribution system under two operating modes of the gas-steam combined cycle unit;

[0053] Step 2.1: Collect the real-time voltage U of the high-voltage power distribution system of the gas-steam combined cycle unit under two operating modes h 、Current I h , power P h , Power Factor Data, and calculate the per-unit value of these data:

[0054] (1) The gas-steam combined cycle unit adopts a two-to-one operation mode

[0055] In this embodiment, when the gas-steam combined cycle unit adopts the two-to-one operation mode, the voltage U h =5.96kV, the voltage reference value is 6kV; current I h =1867.2A, the current reference value is 1867A; power P h =11.13MW, the power reference value is 11.2MW; power factor The power factor reference value is 0.8;

[0056]

[0057] (2) The gas-steam combined cycle unit adopts one-to-one operation mode

[0058] In this embodiment, when the gas-steam combined cycle unit adopts a one-to-one operation mode, the collected 6kV system voltage U h =5.97kV, the voltage reference value is 6kV; current I h =696.7A, the current reference value is 697A; power P h =4.159MW, the power reference value is 4.2MW; power factor The power factor reference value is 0.8.

[0059]

[0060] Step 2.2: Calculate the power balance of the plant's high-voltage power distribution system based on the data collected in step 2.1:

[0061] (1) When the gas-steam combined cycle unit adopts the two-to-one operation mode, the power balance of the plant high-voltage distribution system

[0062]

[0063] (2) When the gas-steam combined cycle unit adopts one-to-one operation mode, the power balance of the plant high-voltage distribution system

[0064]

[0065] Step 3: Calculate the power balance of the plant low-voltage power distribution system (380V) under two operating modes of the gas-steam combined cycle unit;

[0066] Step 3.1: Collect the real-time voltage U of the low-voltage power distribution system for the gas-steam combined cycle unit under two operating modes l 、Current I l , power P l , Power Factor Data, and calculate the per-unit value of these data;

[0067] (1) The gas-steam combined cycle unit adopts a two-to-one operation mode

[0068] In this embodiment, when the gas-steam combined cycle unit adopts the two-to-one operation mode, the collected plant low-voltage distribution system voltage U l =377.6V, the voltage reference value is 380V; current I l =558.7A, current reference value 550A; power P l =211kW, power base value 200kW; power factor The power factor reference value is 0.8, and the per unit value of each data is:

[0069]

[0070] (2) The gas-steam combined cycle unit adopts one-to-one operation mode

[0071] In this embodiment, when the gas-steam combined cycle unit adopts a one-to-one operation mode, the voltage U l =377.8V, the voltage reference value is 380V; current I l =427.2A, current reference value 430A; power P l =161.4kW, power base value 160kW; power factor The power factor reference value is 0.8, and the per unit value of each data is:

[0072]

[0073] Step 3.2: Calculate the power balance of the 380V system under two operation modes of the gas-steam combined cycle unit based on the data collected in step 3.1:

[0074] (1) When the gas-steam combined cycle unit adopts the two-to-one operation mode, the power balance of the 380V system is:

[0075]

[0076] (2) When the gas-steam combined cycle unit adopts one-to-one operation mode, the power balance of the 380V system is:

[0077]

[0078] Step 4: Calculate the contribution of plant power equipment to the plant power balance;

[0079] Step 4.1: Calculate the power balance of the high-voltage power distribution system and the power balance of the low-voltage power distribution system before and after the power equipment is started;

[0080] In this embodiment, the 6kV system voltage U collected before the power equipment of a certain factory is started h0 =5.96kV, current I h0 =1867.2A, power P h0 =11.13MW, power factor 380V system voltage U l0 =377.6V, current I l0 =558.7A, power P l0 =211kW, power factor 6kV system voltage U after startuph1 =5.95kv, current I h1 =1868.1A, power P h1 =11.15MW, power factor 380V system voltage U l1 =376.3V, current I l1 =563.7A, power P l1 =212kW, power factor The 6kV system voltage reference value is 6kV, the current reference value is 1867A, the power reference value is 11.2MW, and the power factor reference value is 0.8; the 380V system voltage reference value is 380V, the current reference value is 550A, the power reference value is 200kW, and the power factor reference value is 0.8.

[0081] According to the calculation method proposed in step 2 and step 3, calculate the power balance δ0 and δ1 of the high-voltage power distribution system before and after the equipment is started. 01 And the power balance degree of the low-voltage power distribution system used in the factory δ t , δ t1 ;

[0082]

[0083]

[0084]

[0085]

[0086] Step 4.2: Calculate the contribution of plant power equipment to the plant power balance;

[0087] Calculate the contribution of plant power equipment to the plant power balance as shown in the following formula:

[0088]

[0089] In this embodiment, the contribution of the auxiliary power equipment to the auxiliary power balance is 5.96%.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope defined by the claims of the present invention.

Claims

1. A method for calculating the balance degree of a power plant power system, characterized in that: Firstly, the influence of the two-on-one operation mode and the one-on-one operation mode on the balance of plant power consumption of gas-steam combined cycle units are analyzed, and the influence factors of the two-on-one and one-on-one operation modes of gas-steam combined cycle units on the balance of plant power consumption are calculated; then, the power balance of the plant high-voltage distribution system and the plant low-voltage distribution system are calculated respectively; finally, the influence of any plant power equipment on the balance of plant power consumption is analyzed, and on the basis of the calculation method of the power balance of the plant high-voltage distribution system and the plant low-voltage distribution system, the contribution of the plant power equipment to the balance of plant power consumption is calculated; The method specifically comprises the following steps: Step 1: Calculate the impact factors of the two-on-one and one-on-one operation modes of the gas-steam combined cycle units on the balance of plant power consumption; Step 1.1: Collect the historical voltage U of the plant high-voltage distribution system when n gas-steam combined cycle units adopt the two-to-one operation mode i0 、Current I i0 , power P i0 , Power Factor i=1, 2, ..., n and n groups adopt one-to-one operation mode, the historical voltage U of the plant high-voltage distribution system i1 、Current I i1 , power P i1 , Power Factor And calculate the per-unit value of these data; Step 1.2: Calculate the impact factors of the two-on-one and one-on-one operation modes of the gas-steam combined cycle units on the balance of plant power consumption; Step 2: Calculate the power balance of the plant's high-voltage power distribution system; Step 2.1: Collect the real-time voltage U of the high-voltage power distribution system used in the factory h 、Current I h , Power P h , Power Factor Data, and calculate the per-unit value of these data; Step 2.2: Calculate the power balance degree δ0 of the plant high-voltage power distribution system according to the per-unit value of the data collected in step 2.1; Step 3: Calculate the power balance of the factory's low-voltage power distribution system; Step 3.1: Collect the real-time voltage U of the low-voltage power distribution system used in the factory l 、Current I l , Power P l , Power Factor Data, and calculate the per-unit value of these data; Step 3.2: Calculate the power balance degree δ of the low-voltage power distribution system for the factory based on the per-unit value of the data collected in step 3.1 t ; Step 4: Calculate the contribution of plant power equipment to the plant power balance; Step 4.1: Calculate the power balance of the high-voltage power distribution system and the power balance of the low-voltage power distribution system before and after the power equipment is started; Step 4.2: Calculate the power balance of the high-voltage power distribution system before and after the power equipment is started, δ0 and δ 01 And the power balance degree of the low-voltage power distribution system used in the factory δ t , δ t1 Calculate the contribution of plant power equipment to the plant power balance; The influence factor φ0 of the two-to-one operation mode of the gas-steam combined cycle units on the balance of plant power consumption described in step 1.2 is shown in the following formula: The influence factor of the one-to-one operation mode of the gas-steam combined cycle unit on the balance of the plant power consumption φ t As shown in the following formula: Among them, U i ′0 is the voltage U i0 The per unit value, I i '0 is the current I i0 The per unit value, P i ′0 is the power P i0 The per unit value of is the power factor The per unit value, U i ′1 is the voltage U i1 The per unit value, I i ′1 is the current I i1 The per unit value, P i1 ′ is the power P i1 The per unit value of is the power factor The per unit value of The power balance of the high-voltage power distribution system for the factory described in step 2.2 is shown in the following formula: Among them, δ0 is the power balance degree of the high-voltage power distribution system used in the factory, U h ′ is the voltage U h The per unit value, I h ' is the current I h The per unit value, P h ′ is the power P h The per unit value of is the power factor The per unit value of The power balance degree δ of the low-voltage power distribution system used in the factory described in step 3.2 t As shown in the following formula: Among them, U l ′ is the voltage U l The per unit value, I l ' is the current I l The per unit value, P l ′ is the power P l The per unit value of The power factor The per unit value of The specific method of step 4.1 is: Collect the voltage U of the high-voltage power distribution system before the power equipment is started h0 、Current I h0 , power P h0 , Power Factor Voltage U of the low voltage power distribution system for the factory l0 、Current I l0 , power P l0 , Power Factor The voltage U of the high-voltage power distribution system after the power equipment is started h1 、Current I h1 , power P h1 , Power Factor System voltage U of the factory low-voltage power distribution system l1 、Current I l1 , power P l1 , Power Factor According to the calculation method of the system power balance in step 2 and step 3, the power balance of the high-voltage power distribution system before and after the power equipment is started is calculated, δ0 and δ 01 And the power balance degree of the low-voltage power distribution system used in the factory δ t , δ t1 ; The contribution of the plant power equipment to the plant power balance calculated in step 4.2 is as shown in the following formula:

Images