阅读说明：本技术 一种基于电动机铭牌参数的安全临界电压计算方法 (A kind of safety critical voltage calculation method based on name plate of motor parameter ) 是由 刘朝章 赵金勇 武巍 卢泽光 张波 陈钰 张志强 张小虎 祝成 张兆斌 魏本成 于 2019-08-22 设计创作，主要内容包括：本发明公开了一种基于电动机铭牌参数的安全临界电压计算方法。本发明包括基于铭牌参数计算临界转差率,利用临界转差率下负载转矩计算安全临界电压,考虑负载转矩特性计算安全临界电压三部分。本发明利用铭牌参数进行感应电动机的安全临界电压计算方法简洁明了,无需实验且准确度高。(The safety critical voltage calculation method based on name plate of motor parameter that the invention discloses a kind of.The present invention includes calculating breakdown slip based on nameplate parameter, calculates safety critical voltage using load torque under breakdown slip, considers that load torque characteristic calculates safety critical voltage three parts.The present invention is concise using the safety critical voltage calculation method that nameplate parameter carries out induction conductivity, without experiment and accuracy height.)

1. a kind of safety critical voltage calculation method based on induction conductivity nameplate parameter is it is characterized in that this method includes three A step:

Step 1 is based on nameplate parameter and calculates breakdown slip；

Step 2 calculates safety critical voltage using load torque under breakdown slip；

Step 3: considering that load torque characteristic calculates safety critical voltage.

2. based on the safety critical voltage calculation method of induction conductivity nameplate parameter described in a kind of claim 1, it is characterized in that Criticality safety voltage is calculated using following formula in its step 2:

Wherein: u_critFor criticality safety voltage, u_nFor induction conductivity voltage rating, k_mFor induction conductivity torque capacity multiple, T_nFor the nominal torque of induction machine, T_l(s_m) for the load torque of the induction conductivity institute band under breakdown slip.

3. based on the safety critical voltage calculation method of induction conductivity nameplate parameter described in a kind of claim 1, it is characterized in that It is as follows that its step 3 considers that load characteristic calculates safety critical voltage:

The safety critical voltage u under for constant torque load_crit,ConTCalculation formula are as follows:

Safety critical voltage u under constant power load_crit,ConPCalculation formula are as follows:

The safety critical voltage u of induction conductivity under blower-pump load_crit,ConFCalculation formula is as follows:Wherein k_mFor induction conductivity torque capacity multiple, T_nFor the specified of induction machine Torque, T₀For the torque of constant torque load, T₁For the constant that constant power load torque does not change with revolutional slip, P_lIt is negative for invariable power Coefficient of the set torque with revolutional slip changing unit, T_aThe constant and T not changed with revolutional slip for blower-pump load torque_bFor wind Machinery pump load torque with revolutional slip changing unit coefficient.

Technical field

The invention belongs to field of power systems, are related to a kind of safety critical potentiometer based on induction conductivity nameplate parameter The method of calculation.

Background technique

Power quality problem more attracts attention.Especially with the largest loss caused by voltage dip in power quality event. Voltage dip also becomes one of the power quality problem that power consumer is concerned about the most.Voltage dip causes motor out of service. The temporary drop degree that motor is able to bear during voltage dip is important parameter, can preferably carry out system guarantor using it The configuration of shield.Traditional theoretical calculation can obtain preferable conclusion, but analysis uses parameter and obtains difficulty.Although simulation method At low cost, effect is also good, but equally exists relevant parameter in simulation modeling and obtain difficult problem；Utilize the side of experiment Method can be very good to detect the voltage dip characteristic of induction conductivity, but is tested in actual production and cause one to motor The damage for determining degree is paid a price also higher, performance difficulty.Thereby, it is possible to the peace of induction conductivity is carried out using nameplate parameter Full critical voltage calculates with the obvious advantage.

Summary of the invention

The technical scheme is that a kind of safety critical voltage calculation method based on induction conductivity nameplate parameter.

A kind of safety critical voltage calculation method, it is characterized in that method includes the following steps:

Step 1 is based on nameplate parameter and calculates breakdown slip

According to the voltage rating u of motor is found out to the nameplate of induction conductivity_n, rated power P_n, rated speed n_n, Number of pole-pairs p and torque capacity multiple k_mSpecific value.It is counted as follows by system frequency f and induction conductivity number of pole-pairs p Calculate synchronous rotational speed:

n_s=60f/p

Rated slip s is calculated using synchronous rotational speed_nFormula is as follows:

Rated slip s is calculated using rated slip_mFormula is as follows:

Step 2 calculates safety critical voltage using load torque under breakdown slip

According to motor load type and characteristic, its load torque T is obtained_l(), and specifically when revolutional slip is critical Revolutional slip s_mWhen load torque be T_l(s_m)。

Utilize rated power, rated slip, system frequency, the nominal torque of induction conductivity number of pole-pairs calculating motor Value T_nIt is as follows:

Using nominal torque, load torque under breakdown slip, torque capacity multiple calculates motor according to the following formula Safety critical voltage u_crit

Step 3: considering that load torque characteristic calculates safety critical voltage

When constant torque load, load torque characteristic T_l,ConT(s) it expresses are as follows:

T_l,ConT(s)=T₀

Wherein T₀It is a constant for the torque of constant torque load；Bringing safety critical voltage expression in step 2 into can obtain, Constant torque load critical voltage u_crit,ConTCalculation formula is as follows:

When constant power load, load torque characteristic T_l,ConP(s) it expresses are as follows:

T_l,ConP(s)=T₁+P_l/(1-s)

Wherein T₁The constant and P not changed with revolutional slip for constant power load torque_lIt is constant power load torque with revolutional slip The coefficient of changing unit；

Above-mentioned torque characteristics is substituted into step 2, the safety that safety critical voltage expression can obtain under constant power load is faced Boundary voltage u_crit,ConPCalculation formula is as follows:

For blower, load of the pumps, torque characteristics is as follows:

T_l(s)=T_a+T_b(1-s)²

Wherein T_aThe constant and T not changed with revolutional slip for blower-pump load torque_bFor blower-pump load torque with turn The coefficient of rate changing unit；

The safety critical voltage u of induction conductivity under blower-pump load_crit,ConFCalculation formula is as follows:

Specific embodiment

Below with reference to specification, elaborate to preferred embodiment.It is emphasized that following the description is only example Property, the range and its application being not intended to be limiting of the invention.

It is simple that the present invention provides one kind, efficiently, is easy to peace when the voltage dip based on name plate of motor parameter of calculating The calculation method of full critical voltage.By taking following induction conductivity relevant calculation process as an example, this method is implemented as follows:

1, breakdown slip s is calculated based on nameplate parameter_m

Pass through the available voltage rating u of name plate of motor parameter_n=10.0kV, rated power P_n=1400kW, specified turn Fast n_n=1492r/min, number of pole-pairs p=2 and torque capacity multiple k_m=2.38.The following n of calculation formula_s=60f/p, Thus breakdown slip s is calculated_m=0.0241；

2, under different loads characteristic safety critical voltage specific calculating

The load module of motor is divided into three classes as follows: constant torque load mark parameter T_l,ConT(s)=1；Constant power load Mark parameter T_l,ConP(s)=0.2+0.8/ (1-s)；Blower, load of the pumps mark parameter T_l,ConF(s)=0.6+0.435 (1-s)²； Then calculation method is as follows:

Constant torque load:

Constant power load:

Blower, load of the pumps:

The foregoing is only a preferred embodiment of the present invention, but scope of protection of the present invention is not limited thereto, In the technical scope disclosed by the present invention, any changes or substitutions that can be easily thought of by anyone skilled in the art, It should be covered by the protection scope of the present invention.Therefore, protection scope of the present invention should be with scope of protection of the claims Subject to.