CN105548767A - Power transformer loss live-line measurement and hot spot temperature prediction system and method - Google Patents

Abstract

The invention discloses a power transformer loss live-line measurement and hot spot temperature prediction system and method. The system comprises a computer, a digital acquisition card, a temperature sensor, a primary voltage transformer, a secondary voltage transformer, a primary current transformer and a secondary current transformer. The output ends of the primary voltage transformer, the secondary voltage transformer, the primary current transformer and the secondary current transformer are connected with the computer through the digital acquisition card, and the output end of the temperature sensor is connected with the computer; the primary voltage transformer and the secondary voltage transformer are respectively arranged at the primary side and the secondary side of a power transformer; the primary current transformer and the secondary current transformer are respectively arranged at the primary side and the secondary side of the power transformer; and the temperature sensor is used for measuring an ambient temperature of an environment in which the power transformer is disposed and a temperature of an oil top layer of the transformer. The method and system provided by the invention can realize loss live-line measurement of the transformer, can predict the hot-spot temperature of the winding of the transformer, and are used for knowing the state of the transformer and guiding reasonable operation of the transformer.

Description

A kind of power transformer loss live line measurement and hot(test)-spot temperature prognoses system and method

Technical field

The invention belongs to technical field of power systems, specifically disclose a kind of power transformer loss live line measurement and hot(test)-spot temperature prognoses system and method.

Background technology

Oil-immersed power transformer is one of nucleus equipment in electric system, and its stable operation controls there is very important impact to the safe reliability of system and operating cost.The size of transformer copper loss and iron loss numerical value is relevant with the manufacturing process of transformer, the method for operation and power supply quality.Transformer loss characteristic reflects on the one hand transformer and runs whether economical rationality, on the other hand also for fault analysis provides diagnosis basis.

While power transformer electric pressure and individual capacity improve constantly, the heat of its transformer sheds problem also more and more obviously, and overheating fault also grows with each passing day on the impact of safe operation of power system and harm.Winding in Power Transformer temperature is too low, then do not make full use of transformer load ability, reduce economic benefit; When temperature is too high, then easily accelerate the aging of insulation, reduce the life-span of transformer.

Summary of the invention

The object of the present invention is to provide a kind of power transformer loss live line measurement and hot(test)-spot temperature prognoses system and method, realize the loss live line measurement of transformer, and can predict hot-spot temperature of transformer, for understanding transformer state, instruct transformer rationally to run.

To achieve these goals, the following technical scheme taked of the present invention:

A kind of power transformer loss live line measurement and temperature prediction system, comprise computing machine, Data Acquisition Card, temperature sensor, original edge voltage mutual inductor, secondary voltage mutual inductor, primary current mutual inductor and secondary current mutual inductor; Original edge voltage mutual inductor, secondary voltage mutual inductor, primary current mutual inductor are connected the input end of Data Acquisition Card with the output terminal of secondary current mutual inductor, the output terminal of Data Acquisition Card is connected computing machine with the output terminal of temperature sensor; Original edge voltage mutual inductor, secondary voltage mutual inductor are separately positioned on former limit and the secondary of power transformer, for former limit and the secondary voltage of Real-time Collection power transformer; Primary current mutual inductor and secondary current mutual inductor are separately positioned on former limit and the secondary of power transformer, for former limit and the secondary current of Real-time Collection power transformer; Temperature sensor is for measuring environment temperature and the transformer oil temperature of top of environment residing for power transformer.

Further, when power transformer runs, electric current, the voltage of the electric current on former limit, voltage and secondary when synchronous acquisition transformer runs, and utilize temperature sensor measurement environment temperature and transformer oil temperature of top, after computer calculate, obtain real-time loss of transformers information.

Further, described loss information comprises transformer copper consumption, iron loss; Transformer copper loss and iron losses computation formula as follows:

Copper loss is:

$P_{Cu}=\frac{1}{T}{\∫}_0^T(v_1-\frac{v_2}{K})\·K\·i_{2}dt$

Iron loss is:

$P_{Fe}=\frac{1}{T}{\∫}_0^T{v}_1(i_1-i_2\·K)dt$

Wherein, v1, i1 are power transformer primary side voltage, current instantaneous value; V2, i2 are power transformer secondary side voltage, current instantaneous value; Power transformer no-load voltage ratio is K; T is computation period.

Further according to hot-spot temperature of transformer accounting equation:

$\left\{\begin{array}{c}{\mathrm{\θ}}_h\left(t\right)={\mathrm{\θ}}_a+{\mathrm{\Δ\θ}}_{oi}+\{{\mathrm{\Δ\θ}}_{or}\×{\[\frac{1+R\×k^2}{1+R}\]}^x+{\mathrm{\Δ\θ}}_{oi}\}\×f_2\left(t\right)+{\mathrm{\Δ\θ}}_{hi}+\{H\×g_r\×k^y-{\mathrm{\Δ\θ}}_{hi}\}\×f_2\left(t\right)\\ f_1\left(t\right)=(1-e^{(-t)/(k_{11}\×{\mathrm{\τ}}_o)})\\ f_2\left(t\right)=k_{21}\×(1-e^{(-t)/(k_{22}\×{\mathrm{\τ}}_w)})-(k_{21}-1)\×(1-e^{(-t)/({\mathrm{\τ}}_o/k_{22})})\\ k=I_h/I_{hr}\end{array}\right.---\left(1\right)$

Wherein: θ _afor environment temperature, Δ θ _oifor initial top-oil temperature liter, Δ θ _orfor top-oil temperature stable state temperature rise under nominal loss, R is the ratio of load loss and open circuit loss under rated current, I _hfor high-pressure side load current effective value, I _hrfor high-pressure side load current ratings, Δ θ _hithe gradient of hot(test)-spot temperature and top-oil temperature during for starting, H is focus coefficient, is 1.1, g to the general value of substation transformer _rfor the difference of winding medial temperature and oily medial temperature under rated current, x, y, k ₁₁, k ₂₁, k ₂₂, τ _o, τ _wfor constant, for the transformer of ONAN radiating mode, its value is respectively 0.8,1.3,0.5,2.0,2.0,210,10, and for the transformer of ONAF radiating mode, its value is respectively 0.8, and 1.3,0.5,2.0,2.0,150,7.

During according to beginning, the difference of top-oil temperature liter and hot(test)-spot temperature and top-oil temperature, bring solving equation group (1) into, the hot(test)-spot temperature of time after can trying to achieve, completes the prediction of hot(test)-spot temperature.

A kind of power transformer loss live line measurement and temperature predicting method, comprise the following steps:

(1) signals collecting:

The former secondary current of synchronous acquisition power transformer, voltage, power transformer environment temperature, electric power transformer oil temperature of top;

(2) loss calculation:

Transformer copper loss and iron losses computation method as follows:

Real-time copper loss is:

$P_{Cu}=\frac{1}{T}{\∫}_0^T(v_1-\frac{v_2}{K})\·K\·i_{2}dt$

Real-time iron loss is:

$P_{Fe}=\frac{1}{T}{\∫}_0^T{v}_1(i_1-i_2\·K)dt$

Wherein, v1, i1 are power transformer primary side voltage, current instantaneous value; V2, i2 are power transformer secondary side voltage, current instantaneous value; Power transformer no-load voltage ratio is K; T is computation period;

(3) prediction and calculation of hot(test)-spot temperature:

According to hot-spot temperature of transformer accounting equation

$\left\{\begin{array}{c}{\mathrm{\θ}}_h\left(t\right)={\mathrm{\θ}}_a+{\mathrm{\Δ\θ}}_{oi}+\{{\mathrm{\Δ\θ}}_{or}\×{\[\frac{1+R\×k^2}{1+R}\]}^x+{\mathrm{\Δ\θ}}_{oi}\}\×f_2\left(t\right)+{\mathrm{\Δ\θ}}_{hi}+\{H\×g_r\×k^y-{\mathrm{\Δ\θ}}_{hi}\}\×f_2\left(t\right)\\ f_1\left(t\right)=(1-e^{(-t)/(k_{11}\×{\mathrm{\τ}}_o)})\\ f_2\left(t\right)=k_{21}\×(1-e^{(-t)/(k_{22}\×{\mathrm{\τ}}_w)})-(k_{21}-1)\×(1-e^{(-t)/({\mathrm{\τ}}_o/k_{22})})\\ k=I_h/I_{hr}\end{array}\right.---\left(1\right)$

Wherein: θ _afor environment temperature, Δ θ _oifor initial top-oil temperature liter, Δ θ _orfor top-oil temperature stable state temperature rise under nominal loss, R is the ratio of load loss and open circuit loss under rated current, I _hfor high-pressure side load current effective value, I _hrfor high-pressure side load current ratings, Δ θ _hithe gradient of hot(test)-spot temperature and top-oil temperature during for starting, H is focus coefficient, is 1.1, g to the general value of substation transformer _rfor the difference of winding medial temperature and oily medial temperature under rated current, x, y, k ₁₁, k ₂₁, k ₂₂, τ _o, τ _wfor constant, for the transformer of ONAN radiating mode, its value is respectively 0.8,1.3,0.5,2.0,2.0,210,10, and for the transformer of ONAF radiating mode, its value is respectively 0.8, and 1.3,0.5,2.0,2.0,150,7;

During according to beginning, the difference of top-oil temperature liter and hot(test)-spot temperature and top-oil temperature, bring solving equation group (1) into, the hot(test)-spot temperature of time after can trying to achieve, completes the prediction of hot(test)-spot temperature.

Relative to prior art, the present invention has following beneficial effect: the present invention can realize the loss live line measurement of transformer, and can predict coiling hot point of transformer temperature, for understanding transformer state, instructs transformer rationally to run.The present invention passes through electric current and the information of voltage of synchronous acquisition transformer primary side and secondary, then utilizes equivalent circuit of transformer, calculates the real-time copper loss of transformer and iron loss.Copper loss and iron loss can reflect transformer operational efficiency, and loss can reflect the problem of transformer inherence extremely.Measures ambient temperature and transformer oil temperature of top simultaneously, calculating transformer hot(test)-spot temperature, instructs transformer rationally to run.

Accompanying drawing explanation

Fig. 1 is power transformer loss live line measurement and temperature prediction system structural representation;

Fig. 2 is power transformer loss live line measurement and temperature prediction system operational flow diagram.

Embodiment

Refer to shown in Fig. 1, a kind of power transformer loss live line measurement of the present invention and hot(test)-spot temperature prognoses system, comprise computing machine, Data Acquisition Card, temperature sensor, original edge voltage mutual inductor, secondary voltage mutual inductor, primary current mutual inductor and secondary current mutual inductor.

Original edge voltage mutual inductor, secondary voltage mutual inductor, primary current mutual inductor are connected the input end of Data Acquisition Card with the output terminal of secondary current mutual inductor, the output terminal of Data Acquisition Card is connected computing machine with the output terminal of temperature sensor.Original edge voltage mutual inductor, secondary voltage mutual inductor are separately positioned on former limit and the secondary of power transformer, for former limit and the secondary voltage of Real-time Collection power transformer; Primary current mutual inductor and secondary current mutual inductor are separately positioned on former limit and the secondary of power transformer, for former limit and the secondary current of Real-time Collection power transformer; Temperature sensor is for measuring environment temperature and the transformer oil temperature of top of environment residing for power transformer.

A kind of power transformer loss live line measurement of the present invention and temperature prediction system are when power transformer runs, electric current, the voltage of the electric current on former limit, voltage and secondary when synchronous acquisition transformer runs, and utilize temperature sensor measurement environment temperature, after computer calculate, real-time loss of transformers information can be obtained, and coiling hot point of transformer temperature can be predicted.

A kind of power transformer loss live line measurement of the present invention and hot(test)-spot temperature Forecasting Methodology, comprise the following steps:

(1) signals collecting:

The current transformer of the former secondary current of synchronous acquisition power transformer, adopts pincer structure, does not affect power transformer work during current measurement.Measuring accuracy is high, can reach 0.5 grade.

The voltage transformer (VT) of synchronous acquisition transformer primary secondary voltage, utilizes large resistance to carry out dividing potential drop, and is directed to power frequency and carries out phase correction, and measurement result accurately and reliably.

The secondary side access Data Acquisition Card of current transformer and voltage transformer (VT), Data Acquisition Card picking rate is fast, and sample frequency is 1000kHz, can well recovering signal.Transformer primary secondary voltage electric current is totally four road signal synchronous collections, triggers sampling by unified clock trigger source, ensures the synchronism of voltage and current signal.

Carried out the measurement of environment temperature by four temperature sensors, temperature sensor is evenly arranged in the surrounding of power transformer, and measures ambient temperature, effectively avoids the randomness that single temperature sensor measurement temperature is brought simultaneously.

Fibre optic temperature sensor is adopted to carry out the measurement of transformer oil top-oil temperature.

(2) loss calculation:

Transformer copper loss and iron losses computation method as follows:

V1, i1 are power transformer primary side voltage, current instantaneous value; V2, i2 are power transformer secondary side voltage, current instantaneous value; Power transformer no-load voltage ratio is K; T is computation period, general T=1s; Can calculate real-time copper loss is:

$P_{Cu}=\frac{1}{T}{\∫}_0^T(v_1-\frac{v_2}{K})\·K\·i_{2}dt$

Iron loss is:

$P_{Fe}=\frac{1}{T}{\∫}_0^T{v}_1(i_1-i_2\·K)dt$

(3) prediction and calculation of hot(test)-spot temperature:

According to hot-spot temperature of transformer accounting equation

$\left\{\begin{array}{c}{\mathrm{\θ}}_h\left(t\right)={\mathrm{\θ}}_a+{\mathrm{\Δ\θ}}_{oi}+\{{\mathrm{\Δ\θ}}_{or}\×{\[\frac{1+R\×k^2}{1+R}\]}^x+{\mathrm{\Δ\θ}}_{oi}\}\×f_2\left(t\right)+{\mathrm{\Δ\θ}}_{hi}+\{H\×g_r\×k^y-{\mathrm{\Δ\θ}}_{hi}\}\×f_2\left(t\right)\\ f_1\left(t\right)=(1-e^{(-t)/(k_{11}\×{\mathrm{\τ}}_o)})\\ f_2\left(t\right)=k_{21}\×(1-e^{(-t)/(k_{22}\×{\mathrm{\τ}}_w)})-(k_{21}-1)\×(1-e^{(-t)/({\mathrm{\τ}}_o/k_{22})})\\ k=I_h/I_{hr}\end{array}\right.---\left(1\right)$

Wherein: θ _afor environment temperature, Δ θ _oifor initial top-oil temperature liter, Δ θ _orfor top-oil temperature stable state temperature rise under nominal loss, R is the ratio of load loss and open circuit loss under rated current, I _hfor high-pressure side load current effective value, I _hrfor high-pressure side load current ratings, Δ θ _hithe gradient of hot(test)-spot temperature and top-oil temperature during for starting, H is focus coefficient, is 1.1, g to the general value of substation transformer _rfor the difference of winding medial temperature and oily medial temperature under rated current, x, y, k ₁₁, k ₂₁, k ₂₂, τ _o, τ _wfor constant, for the transformer of ONAN radiating mode, its value is respectively 0.8,1.3,0.5,2.0,2.0,210,10, and for the transformer of ONAF radiating mode, its value is respectively 0.8, and 1.3,0.5,2.0,2.0,150,7.

During according to beginning, the difference of top-oil temperature liter and hot(test)-spot temperature and top-oil temperature, bring solving equation group (1) into, the hot(test)-spot temperature of time after can trying to achieve, completes the prediction of hot(test)-spot temperature.

Claims (5)

1. power transformer loss live line measurement and a temperature prediction system, is characterized in that, comprises computing machine, Data Acquisition Card, temperature sensor, original edge voltage mutual inductor, secondary voltage mutual inductor, primary current mutual inductor and secondary current mutual inductor; Original edge voltage mutual inductor, secondary voltage mutual inductor, primary current mutual inductor are connected the input end of Data Acquisition Card with the output terminal of secondary current mutual inductor, the output terminal of Data Acquisition Card is connected computing machine with the output terminal of temperature sensor; Original edge voltage mutual inductor, secondary voltage mutual inductor are separately positioned on former limit and the secondary of power transformer, for former limit and the secondary voltage of Real-time Collection power transformer; Primary current mutual inductor and secondary current mutual inductor are separately positioned on former limit and the secondary of power transformer, for former limit and the secondary current of Real-time Collection power transformer; Temperature sensor is for measuring environment temperature and the transformer oil temperature of top of environment residing for power transformer.

2. a kind of power transformer loss live line measurement according to claim 1 and temperature prediction system, it is characterized in that, when power transformer runs, electric current, the voltage of the electric current on former limit, voltage and secondary when synchronous acquisition transformer runs, and utilize temperature sensor measurement environment temperature and transformer oil temperature of top, after computer calculate, obtain real-time loss of transformers information, and hot-spot temperature of transformer is calculated.

3. a kind of power transformer loss live line measurement according to claim 2 and temperature prediction system, is characterized in that, described loss information comprises transformer copper consumption, iron loss; Transformer copper loss and iron losses computation formula as follows:

Copper loss is:

$P_{Cu}=\frac{1}{T}{\∫}_0^T(v_1-\frac{v_2}{K})\·K\·i_{2}dt$

Iron loss is:

$P_{Fe}=\frac{1}{T}{\∫}_0^T{v}_1(i_1-i_2\·K)dt$

Wherein, v1, i ₁for power transformer primary side voltage, current instantaneous value; v ₂, i ₂for power transformer secondary side voltage, current instantaneous value; Power transformer no-load voltage ratio is K; T is computation period.

4. a kind of power transformer loss live line measurement according to claim 3 and temperature prediction system, it is characterized in that, described computing machine also calculates power transformer hot(test)-spot temperature;

Hot-spot temperature of transformer θ _ht the accounting equation of () is:

$\left\{\begin{array}{c}{\mathrm{\θ}}_h\left(t\right)={\mathrm{\θ}}_a+{\mathrm{\Δ\θ}}_{oi}+\{{\mathrm{\Δ\θ}}_{or}\×{\[\frac{1+R\×k^2}{1+R}\]}^x-{\mathrm{\Δ\θ}}_{oi}\}\×f_2\left(t\right)+{\mathrm{\Δ\θ}}_{hi}+\{H\×g_r\×k^y-{\mathrm{\Δ\θ}}_{hi}\}\×f_2\left(t\right)\\ f_1\left(t\right)=(1-e^{(-t)/(k_{11}\×{\mathrm{\τ}}_o)})\\ f_2\left(t\right)=k_{21}\×(1-e^{(-t)/(k_{22}\×{\mathrm{\τ}}_w)})-(k_{21}-1)\×(1-e^{(-t)/({\mathrm{\τ}}_o/k_{22})})\\ k=I_h/I_{hr}\end{array}\right.---\left(1\right)$

Wherein: θ _afor environment temperature, Δ θ _oifor initial top-oil temperature liter, Δ θ _orfor top-oil temperature stable state temperature rise under nominal loss, R is the ratio of load loss and open circuit loss under rated current, I _hfor high-pressure side load current effective value, I _hrfor high-pressure side load current ratings, Δ θ _hithe gradient of hot(test)-spot temperature and top-oil temperature during for starting, H is focus coefficient, is 1.1, g to substation transformer value _rfor the difference of winding medial temperature and oily medial temperature under rated current, x, y, k ₁₁, k ₂₁, k ₂₂, τ _o, τ _wfor constant, for the transformer of ONAN radiating mode, its value is respectively 0.8,1.3,0.5,2.0,2.0,210,10, and for the transformer of ONAF radiating mode, its value is respectively 0.8, and 1.3,0.5,2.0,2.0,150,7.

5. power transformer loss live line measurement and a temperature predicting method, is characterized in that, comprises the following steps:

(1) signals collecting:

The former secondary current of synchronous acquisition power transformer, voltage, power transformer environment temperature;

(2) loss calculation:

(2.1) transformer copper loss and iron losses computation method as follows:

Real-time copper loss is:

$P_{Cu}=\frac{1}{T}{\∫}_0^T(v_1-\frac{v_2}{K})\·K\·i_{2}dt$

Real-time iron loss is:

$P_{Fe}=\frac{1}{T}{\∫}_0^T{v}_1(i_1-i_2\·K)dt$

Wherein, v1, i1 are power transformer primary side voltage, current instantaneous value; V2, i2 are power transformer secondary side voltage, current instantaneous value; Power transformer no-load voltage ratio is K; T is computation period;

(3) hot(test)-spot temperature calculates: during according to beginning, the difference of top-oil temperature liter and hot(test)-spot temperature and top-oil temperature, and bring solving equation group (1) into, the hot(test)-spot temperature of time after trying to achieve, completes the prediction of hot(test)-spot temperature;

The accounting equation of hot-spot temperature of transformer is:

$\left\{\begin{array}{c}{\mathrm{\θ}}_h\left(t\right)={\mathrm{\θ}}_a+{\mathrm{\Δ\θ}}_{oi}+\{{\mathrm{\Δ\θ}}_{or}\×{\[\frac{1+R\×k^2}{1+R}\]}^x-{\mathrm{\Δ\θ}}_{oi}\}\×f_2\left(t\right)+{\mathrm{\Δ\θ}}_{hi}+\{H\×g_r\×k^y-{\mathrm{\Δ\θ}}_{hi}\}\×f_2\left(t\right)\\ f_1\left(t\right)=(1-e^{(-t)/(k_{11}\×{\mathrm{\τ}}_o)})\\ f_2\left(t\right)=k_{21}\×(1-e^{(-t)/(k_{22}\×{\mathrm{\τ}}_w)})-(k_{21}-1)\×(1-e^{(-t)/({\mathrm{\τ}}_o/k_{22})})\\ k=I_h/I_{hr}\end{array}\right.---\left(1\right)$

Wherein: θ _afor environment temperature, Δ θ _oifor initial top-oil temperature liter, Δ θ _orfor top-oil temperature stable state temperature rise under nominal loss, R is the ratio of load loss and open circuit loss under rated current, I _hfor high-pressure side load current effective value, I _hrfor high-pressure side load current ratings, Δ θ _hithe gradient of hot(test)-spot temperature and top-oil temperature during for starting, H is focus coefficient, is 1.1, g to substation transformer value _rfor the difference of winding medial temperature and oily medial temperature under rated current, x, y, k ₁₁, k ₂₁, k ₂₂, τ _o, τ _wfor constant, for the transformer of ONAN radiating mode, its value is respectively 0.8,1.3,0.5,2.0,2.0,210,10, and for the transformer of ONAF radiating mode, its value is respectively 0.8, and 1.3,0.5,2.0,2.0,150,7.