<PAGE>

                                                                    Exhibit 4.02

                                                                  CONFORMED COPY

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                          SUPPLEMENTAL INDENTURE NO. 1


                                      FROM


                              NORTHERN STATES POWER
                                     COMPANY
                            (A WISCONSIN CORPORATION)

                                       TO


                               FIRSTAR BANK, N. A.

                                     TRUSTEE

                                     -------


                                   DATED AS OF

                               SEPTEMBER 15, 2000


                            SUPPLEMENTAL TO INDENTURE
                          DATED AS OF SEPTEMBER 1, 2000



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<PAGE>

                                                 TABLE OF CONTENTS

<TABLE>
<CAPTION>

<S>                                                                                                 <C>
         Parties..................................................................................  1
         Recitals.................................................................................  1

                                                    ARTICLE ONE
                                        RELATION TO INDENTURE; DEFINITIONS

         SECTION 1.01      Integral Part of Indenture.............................................  2
         SECTION 1.02      (a)    Definitions.....................................................  2
                           (b)    References to Articles and Sections.............................  2
                           (c)    Terms Referring to this Supplemental Indenture..................  2

                                                   ARTICLE TWO
                                        7.64% SENIOR NOTES, SERIES DUE 2008

         SECTION 2.01      Designation and Principal Amount.......................................  2
         SECTION 2.02      Stated Maturity Date...................................................  2
         SECTION 2.03      Interest Payment Dates.................................................  2
         SECTION 2.04      Office for Payment.....................................................  2
         SECTION 2.05      Redemption Provisions..................................................  2
         SECTION 2.06      Authorized Denominations...............................................  4
         SECTION 2.07      Occurrence of Release Date.............................................  4
         SECTION 2.08      Form of 7.64% Senior Notes, Series Due 2008............................  4

                                                  ARTICLE THREE
                                                    COVENANTS

         SECTION 3.01      Limitation on Liens....................................................  4
         SECTION 3.02      Certain Definitions....................................................  5


                                                  ARTICLE FOUR
                                                  MISCELLANEOUS

         SECTION 4.01      Recitals of fact, except as stated, are statements
                           of the Company.........................................................  7
         SECTION 4.02      Supplemental Indenture to be construed as a part
                           of the Indenture.......................................................  7
         SECTION 4.03      (a)    Trust Indenture Act to control..................................  8
                           (b)    Severability of provisions contained in
                                  Supplemental Indenture and Notes................................  8

         SECTION 4.04      References to either party in Supplemental Indenture
                           include successors or assigns..........................................  8

</TABLE>

(i)

<PAGE>

<TABLE>
<CAPTION>

<S>                                                                                           <C>
         SECTION 4.05      (a)    Provision for execution in counterparts.........................  8
                           (b)    Table of Contents and descriptive headings
                                  of Articles not to affect meaning...............................  8

         Exhibit A - Form of 7.64% Senior Notes, Series due 2008

</TABLE>













(ii)

<PAGE>

SUPPLEMENTAL INDENTURE No. 1, made as of the 15th day of September, 2000, by and
between NORTHERN STATES POWER COMPANY, a corporation duly organized and existing
under the laws of the State of Wisconsin (the "Company"), and FIRSTAR BANK, N.
A., a national banking association organized and existing under the laws of the
United States, as trustee (the "Trustee"):

WITNESSETH:

         WHEREAS, the Company has heretofore executed and delivered its
Indenture (hereinafter referred to as the "Indenture"), made as of September 1,
2000; and

         WHEREAS, Section 2.5 of the Indenture provides that Securities shall be
issued in series and that a Company Order shall specify the terms of each
series; and

         WHEREAS, the Company has this day delivered a Company Order setting
forth the terms of a series of Securities designated "7.64% Senior Notes, Series
due 2008" (hereinafter sometimes referred to as the "Notes due 2008"); and

         WHEREAS, Section 12.1 of the Indenture provides that the Company and
the Trustee may enter into indentures supplemental thereto for the purposes,
among others, of establishing the form of Securities or establishing or
reflecting any terms of any Security and adding to the covenants of the Company;
and

         WHEREAS, the execution and delivery of this Supplemental Indenture No.
1 (herein, "this Supplemental Indenture") have been duly authorized by a
resolution adopted by the Board of Directors of the Company;

         NOW, THEREFORE, THIS INDENTURE WITNESSETH:

         That in order to set forth the terms and conditions upon which the
Notes due 2008 are, and are to be, authenticated, issued and delivered, and in
consideration of the premises of the purchase and acceptance of the Notes due
2008 by the Holders thereof and the sum of one dollar duly paid to it by the
Trustee at the execution of this Supplemental Indenture, the receipt whereof is
hereby acknowledged, the Company covenants and agrees with the Trustee for the
equal and proportionate benefit of the respective Holders from time to time of
the Notes due 2008, as follows:


                                       1
<PAGE>

                                   ARTICLE ONE
                       RELATION TO INDENTURE; DEFINITIONS

         SECTION 1.01 This Supplemental Indenture constitutes an integral part
         of the Indenture.

         SECTION 1.02 For all purposes of this Supplemental Indenture:

         (a)      Capitalized terms used herein without definition shall have
                  the meanings specified in the Indenture;

         (b)      All references herein to Articles and Sections, unless
                  otherwise specified, refer to the corresponding Articles and
                  Sections of this Supplemental Indenture; and

         (c)      The terms "hereof," "herein," "hereby," "hereto," "hereunder"
                  and "herewith" refer to this Supplemental Indenture.

                                   ARTICLE TWO
                       7.64% SENIOR NOTES, SERIES DUE 2008


         SECTION 2.01 There shall be a series of Securities designated the
         "7.64% Senior Notes, Series due 2008" (the "Notes due 2008"). The Notes
         due 2008 shall be limited to $80,000,000 aggregate principal amount.

         SECTION 2.02 Except as otherwise provided in Section 2.05 hereof, the
         principal amount of the Notes due 2008 shall be payable on the stated
         maturity date of October 1, 2008.

         SECTION 2.03 The Notes due 2008 shall be dated their date of
         authentication as provided in the Indenture and shall bear interest
         from their date at the rate of 7.64% per annum, payable semi-annually
         on April 1 and October 1 of each year, commencing April 1, 2001. The
         Regular Record Dates with respect to such April 1 and October 1
         interest payment dates shall be March 15 and September 15,
         respectively. Principal and interest shall be payable to the persons
         and in the manner provided in Sections 2.4 and 2.12 of the Indenture.

         SECTION 2.04 The Notes due 2008 shall be payable at the corporate trust
         office of the Trustee and at the offices of such paying agents as the
         Company may appoint by Company Order in the future.

         SECTION 2.05 The Company may redeem the Notes due 2008 at any time, in
         whole or in part, at a redemption price equal to the greater of (i) the
         principal amount of such Notes due 2008 to be redeemed or (ii) the sum
         of the present values of the remaining scheduled payments of principal
         and interest thereon,

                                       2
<PAGE>

         discounted to the date of redemption on a semi-annual basis (assuming
         a 360-day year consisting of twelve 30-day months) at the Treasury
         Yield (as defined below) plus 15 basis points, plus in each case
         accrued interest thereon to the date of redemption.

                  "Treasury Yield" means, with respect to any redemption date,
         the rate per annum equal to the semiannual equivalent yield to maturity
         of the Comparable Treasury Issue, assuming a price for the Comparable
         Treasury Issue (expressed as a percentage of its principal amount)
         equal to the Comparable Treasury Price for the redemption date.

                  "Comparable Treasury Issue" means the United States Treasury
         security selected by an Independent Investment Banker as having a
         maturity comparable to the remaining term of the Notes due 2008 that
         would be utilized, at the time of selection and in accordance with
         customary financial practice, in pricing new issues of corporate debt
         securities of comparable maturity to the remaining term of the Notes.

                  "Independent Investment Banker" means Salomon Smith Barney
         Inc. or its successor or, if such firm is unwilling or unable to select
         the Comparable Treasury Issue, one of the remaining Reference Treasury
         Dealers appointed by the Trustee after consultation with the Company.

                  "Comparable Treasury Price" means, with respect to any
         redemption date, (i) the average of the bid and asked prices for the
         Comparable Treasury Issue (expressed in each case as a percentage of
         its principal amount) on the third business day preceding such
         redemption date, as set forth in the daily statistical release (or any
         successor release) published by the Federal Reserve Bank of New York
         and designated "Composite 3:30 p.m. Quotations for U.S. Government
         Securities" or (ii) if that release (or any successor release) is not
         published or does not contain such prices on such business day, (A) the
         average of the Reference Treasury Dealer Quotations for such redemption
         date, after excluding the highest and lowest such Reference Treasury
         Dealer Quotations for such redemption date, or (B) if fewer than four
         such Reference Treasury Dealer Quotations are obtained, then the
         average of all such Quotations.

                  "Reference Treasury Dealer Quotations" means, with respect to
         each Reference Treasury Dealer and any redemption date, the average, as
         determined by the Debt Trustee, of the bid and asked prices for the
         Comparable Treasury Issue (expressed in each case as a percentage of
         its principal amount) quoted in writing to the Trustee by such
         Reference Treasury Dealer at 5:00 p.m. on the third business day
         preceding such redemption date.

                  "Reference Treasury Dealer" means (i) each of Salomon Smith
         Barney Inc. and any other primary U.S. Government Securities dealer in
         New York City

                                       3
<PAGE>

         (a "Primary Treasury Dealer") designated by, and not affiliated with,
         Salomon Smith Barney Inc. provided, however, that if Salomon Smith
         Barney Inc. or any of its designees shall cease to be a Primary
         Treasury Dealer, the Company shall substitute another Primary Treasury
         Dealer as a substitute for such entity and (ii) any other Primary
         Treasury Dealer selected by the Company

                  The Notes due 2008 shall not be subject to any sinking fund.

         SECTION 2.06 The Notes due 2008 shall be issued in fully registered
         form without coupons in denominations of $1,000 and integral multiples
         thereof.

         SECTION 2.07 The Notes due 2008 shall be issued as unsecured general
         obligations of the Company. The Notes due 2008, and all other Notes
         issued or to be issued under the Indenture, will not be secured by
         first mortgage bonds of the Company and will not be entitled to the
         lien of or the benefits provided by the Supplemental and Restated Trust
         Indenture, dated March 1, 1991, from the Company to Firstar Trust
         Company, as trustee.

         SECTION 2.08 The Notes due 2008 shall initially be in the form attached
         as Exhibit A hereto.

                                  ARTICLE THREE
                                    COVENANTS

         SECTION 3.01. So long as there remain outstanding any Notes due 2008,
         the Company will not create or suffer to be created or to exist any
         mortgage, pledge, security interest, or other lien (collectively,
         "Lien") on any of its utility properties or assets now owned or
         hereafter acquired to secure any indebtedness, without making effective
         provision whereby the Notes due 2008 shall be equally and ratably
         secured with any and all such indebtedness and with any other
         indebtedness similarly entitled to be equally and ratably secured.
         However, this restriction shall not apply to or prevent the creation or
         existence of:

                  (1) the Mortgage securing the Company's First Mortgage Bonds
                  or any indenture supplemental thereto subjecting any property
                  to the Lien thereof or confirming the Lien thereof upon any
                  property, whether now owned or hereafter acquired;

                  (2) Liens on property existing at the time of acquisition or
                  construction of such property (or created within one year
                  after completion of such acquisition or construction), whether
                  by purchase, merger, construction or otherwise or to secure
                  the payment of all or any part of the purchase price or
                  construction cost thereof, including the extension of any such
                  Liens to repairs, renewals, replacements, substitutions,
                  betterments, additions,

                                       4
<PAGE>

                  extensions and improvements then or thereafter made on the
                  property subject thereto;

                  (3) any extensions, renewals or replacements (or successive
                  extensions, renewals or replacements), in whole or in part, of
                  Liens permitted by the foregoing clauses (1) and (2);

                  (4) the pledge of any bonds or other securities at any time
                  issued under any of the Liens permitted by clauses (1), (2) or
                  (3); or

                  (5) Permitted Encumbrances;

                  Further, this restriction shall not apply to or prevent the
                  creation or existence of leases made, or existing on property
                  acquired, in the ordinary course of business.

         SECTION 3.02 Certain Definitions.

                  "Mortgage" means the lien of the first mortgage pursuant to
         the Supplemental and Restated Trust Indenture, dated as of March 1,
         1991, from the Company to Firstar Trust Company, as trustee (the "First
         Mortgage Indenture"), securing the Company's First Mortgage Bonds.

                  "Permitted Encumbrances" means any of the following:

         (1) Liens of taxes, assessments or governmental charges for the then
         current year and taxes, assessments or governmental charges not then
         delinquent; Liens for workers' compensation awards and similar
         obligations not then delinquent; mechanics', laborers', material men's
         and similar Liens not then delinquent; and any of such Liens, whether
         or not delinquent, whose validity is at the time being contested in
         good faith by the Company;

         (2) Liens and charges incidental to construction or current operations
         which have not at the time been filed or asserted or the payment of
         which has been adequately secured or which, in the opinion of counsel,
         are not material in amount;

         (3) Liens, securing obligations neither assumed by the Company nor on
         account of which any of them customarily pays interest directly or
         indirectly, existing, either at the date hereof, or, as to property
         hereafter acquired, at the time of acquisition by the Company;

         (4) Any right which any municipal or governmental body or agency may
         have by virtue of any franchise, license, contract or statute to
         purchase, or designate a purchaser of or order the sale of, any
         property of the Company upon payment of

                                       5
<PAGE>

         reasonable compensation therefor, or to terminate any franchise,
         license or other rights or to regulate the property and business of
         the Company;

         (5) The Lien of judgments covered by insurance, or upon appeal and
         covered, if necessary, by the filing of an appeal bond, or if not so
         covered not exceeding at any one time $1,000,000 in aggregate amount;

         (6) Easements or reservations in respect of any property of the Company
         for the purpose of roads, pipelines, utility transmission and
         distribution lines or other rights-of- way and similar purposes, zoning
         ordinances, regulations, reservations, restrictions, covenants, party
         wall agreements, conditions of record and other encumbrances (other
         than to secure the payment of money), none of which in the opinion of
         counsel are such as to interfere with the proper operation and
         development of the property affected thereby in the business of the
         Company for the use intended;

         (7) Any Lien or encumbrance, moneys sufficient for the discharge of
         which have been deposited in trust with the Trustee hereunder or with
         the trustee or mortgagee under the instrument evidencing such Lien or
         encumbrance, with irrevocable authority to the Trustee hereunder or to
         such other trustee or mortgagee to apply such moneys to the discharge
         of such Lien or encumbrance to the extent required for such purpose;

         (8) Any defects of title and any terms, conditions, agreements,
         covenants, exceptions and reservations expressed or provided in deeds
         or other instruments, respectively, under and by virtue of which the
         Company has acquired any property or shall hereafter acquire any
         property, none of which, in the opinion of counsel, materially
         adversely affects the operation of the properties of the Company;

         (9) The pledge of cash or marketable securities for the purpose of
         obtaining any indemnity, performance or other similar bonds in the
         ordinary course of business, or as security for the payment of taxes or
         other assessments being contested in good faith, or for the purpose of
         obtaining a stay or discharge in the course of any legal proceedings;

         (10) The pledge or assignment in the ordinary course of business of
         electricity, gas (either natural or artificial) or steam, accounts
         receivable or customers' installment paper;

         (11) Rights reserved to or vested in others to take or receive any part
         of the electricity, gas (either natural or artificial), steam or any
         by-products thereof generated or produced by or from any properties of
         the Company or with respect to any other rights concerning electricity,
         gas (either natural or artificial) or steam

                                       6
<PAGE>

         supply, transportation, or storage which are in use in the ordinary
         course of the electricity, gas (either natural or artificial) or steam
         business;

         (12) Any landlord's Lien;

         (13) Liens created or assumed by the Company in connection with the
         issuance of debt securities, the interest on which is excludable from
         the gross income of the holders of such securities pursuant to Section
         103 of the Internal Revenue Code of 1986, or any successor section, for
         purposes of financing, in whole or in part, the acquisition or
         construction of property to be used by the Company, but such Liens
         shall be limited to the property so financed (and the real estate on
         which such property is to be located);

         (14) Liens affixing to property of the Company at the time a Person
         consolidates with or merges into, or transfers all or substantially all
         of its assets to, the Company, provided that in the opinion of the
         Board or Company management (evidenced by a certified Board resolution
         or an Officers' Certificate delivered to the Trustee) the property
         acquired pursuant to the consolidation, merger or asset transfer is
         adequate security for the Lien; and

         (15) Liens or encumbrances not otherwise permitted if, at the time of
         incurrence and after giving effect thereto, the aggregate of all such
         Permitted Encumbrances of the Company secured thereby does not exceed
         10% of Tangible Net Worth.

                  "Tangible Net Worth" means (i) common stockholders' equity
         appearing on the most recent balance sheet of the Company prepared in
         accordance with generally accepted accounting principles less (ii)
         intangible assets (excluding intangible assets recoverable through
         rates as prescribed by applicable regulatory authorities).

                                  ARTICLE FOUR
                                  MISCELLANEOUS

         SECTION 4.01 The recitals of fact herein and in the Notes due 2008
         (except the Trustee's Certificate) shall be taken as statements of the
         Company and shall not be construed as made by the Trustee.

         SECTION 4.02 This Supplemental Indenture shall be construed in
         connection with and as a part of the Indenture.

                                       7
<PAGE>

         SECTION 4.03

         (a)      If any provision of this Supplemental Indenture limits,
                  qualifies, or conflicts with another provision of the
                  Indenture required to be included in indentures qualified
                  under the Trust Indenture Act of 1939 (as enacted prior to the
                  date of this Supplemental Indenture) by any of the provisions
                  of Sections 310 to 317, inclusive, of said Act, such required
                  provisions shall control.

         (b)      In case any one or more of the provisions contained in this
                  Supplemental Indenture or in the notes issued hereunder should
                  be invalid, illegal, or unenforceable in any respect, the
                  validity, legality and enforceability of the remaining
                  provisions contained herein and therein shall not in any way
                  be affected, impaired, prejudiced or disturbed thereby.

         SECTION 4.04 Whenever in this Supplemental Indenture either of the
         parties hereto is named or referred to, this shall be deemed to include
         the successors or assigns of such party, and all the covenants and
         agreements in this Supplemental Indenture contained by or on behalf of
         the Company or by or on behalf of the Trustee shall bind and inure to
         the benefit of the respective successors and assigns of such parties,
         whether so expressed or not.

         SECTION 4.05

         (a)      This Supplemental Indenture may be simultaneously executed in
                  several counterparts, and all said counterparts executed and
                  delivered, each as an original, shall constitute but one and
                  the same instrument.

         (b)      The Table of Contents and the descriptive headings of the
                  several Articles of this Supplemental Indenture were
                  formulated, used and inserted in this Supplemental Indenture
                  for convenience only and shall not be deemed to affect the
                  meaning or construction of any of the provisions hereof.





                                       8
<PAGE>

         IN WITNESS WHEREOF, NORTHERN STATES POWER COMPANY has caused this
Supplemental Indenture to be signed by its President or a Vice President, and
attested by its Secretary or an Assistant Secretary and FIRSTAR BANK, N.A., has
caused this Supplemental Indenture to be signed by its President, Vice
President, Assistant Vice President or authorized Corporate Trust Officer, and
attested by an authorized officer, this 15th day of September, 2000.

                                              NORTHERN STATES POWER COMPANY


                                              By:  /s/ PAUL E. PENDER
                                                 ------------------------------
                                              PAUL E. PENDER, VICE PRESIDENT AND
                                              TREASURER


ATTEST:

/s/ CATHERINE J. CLEVELAND
-----------------------------
CATHERINE J. CLEVELAND,
ASSISTANT CORPORATE SECRETARY


                                                FIRSTAR BANK, N.A., AS TRUSTEE

                                                By: /s/ JAMES MOLL
                                                   -----------------------------
                                                JAMES MOLL,
                                                VICE PRESIDENT AND TRUST OFFICER


ATTEST:

     /S/ BRIAN J. KABBES
     --------------------------------
     BRIAN J. KABBES,
     VICE PRESIDENT AND TRUST OFFICER








                                       9
<PAGE>

                                    EXHIBIT A


                                     FORM OF
                       7.64% SENIOR NOTES, SERIES DUE 2008

REGISTERED                                                            REGISTERED

         THIS NOTE IS A GLOBAL SECURITY REGISTERED IN THE NAME OF THE DEPOSITORY
(REFERRED TO HEREIN) OR A NOMINEE THEREOF AND, UNLESS AND UNTIL IT IS EXCHANGED
IN WHOLE OR IN PART FOR THE INDIVIDUAL NOTES REPRESENTED HEREBY, THIS GLOBAL
SECURITY MAY NOT BE TRANSFERRED EXCEPT AS A WHOLE BY THE DEPOSITORY TO A NOMINEE
OF THE DEPOSITORY OR BY A NOMINEE OF THE DEPOSITORY TO THE DEPOSITORY OR ANOTHER
NOMINEE OF THE DEPOSITORY OR BY THE DEPOSITORY OR ANY SUCH NOMINEE TO A
SUCCESSOR DEPOSITORY OR A NOMINEE OF SUCH SUCCESSOR DEPOSITORY. UNLESS THIS
GLOBAL SECURITY IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY
TRUST COMPANY (55 WATER STREET, NEW YORK, NEW YORK), TO THE TRUSTEE FOR
REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS
REGISTERED IN THE NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN
AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS
MADE TO CEDE & CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF,
CEDE & CO., HAS AN INTEREST HEREIN.

                          NORTHERN STATES POWER COMPANY
             (INCORPORATED UNDER THE LAWS OF THE STATE OF WISCONSIN)

                       7.64% SENIOR NOTE, SERIES DUE 2008

CUSIP:                                                     NUMBER:
       665789AQ6

ORIGINAL ISSUE DATE(S):                                    PRINCIPAL AMOUNT(S):
       October 2, 2000                                          $80,000,000


INTEREST RATE:                                             MATURITY DATE:
       7.64%                                                    October 1, 2008


<PAGE>

         NORTHERN STATES POWER COMPANY, a corporation of the State of Wisconsin
(the "COMPANY"), for value received hereby promises to pay to Cede & Co. or
registered assigns, the principal sum of

                                                                       DOLLARS

on the Maturity Date set forth above, and to pay interest thereon from the
Original Issue Date (or if this Global Security has two or more Original Issue
Dates, interest shall, beginning on each such Original Issue Date, begin to
accrue for that part of the principal amount to which that Original Issue Date
is applicable) set forth above or from the most recent Interest Payment Date to
which interest has been paid or duly provided for, semiannually in arrears on
the April 1 and October 1 in each year, commencing on April 1, 2001, at the per
annum Interest Rate set forth above, until the principal hereof is paid or made
available for payment. No interest shall accrue on the Maturity Date, so long as
the principal amount of this Global Security is paid on the Maturity Date. The
interest so payable and punctually paid or duly provided for on any such
Interest Payment Date will, as provided in the Indenture, be paid to the Person
in whose name this Note is registered at the close of business on the Regular
Record Date for such interest, which shall be the March 15 or September 15, as
the case may be, next preceding such Interest Payment Date; provided, that the
first Interest Payment Date for any part of this Note, the Original Issue Date
of which is after a Regular Record Date but prior to the applicable Interest
Payment Date, shall be the Interest Payment Date following the next succeeding
Regular Record Date; and provided, that interest payable on the Maturity Date
set forth above or, if applicable, upon redemption or acceleration, shall be
payable to the Person to whom principal shall be payable. Except as otherwise
provided in the Indenture (as defined below), any such interest not so
punctually paid or duly provided for will forthwith cease to be payable to the
Holder on such Regular Record Date and shall be paid to the Person in whose name
this Note is registered at the close of business on a Special Record Date for
the payment of such defaulted interest to be fixed by the Trustee, notice
whereof shall be given to Securityholders not more than fifteen days or fewer
than ten days prior to such Special Record Date. On or before Noon, New York
City time, or such other time as shall be agreed upon between the Trustee and
the Depository, of the day on which such payment of interest is due on this
Global Security (other than maturity), the Trustee shall pay to the Depository
such interest in same day funds. On or before Noon, New York City time, or such
other time as shall be agreed upon between the Trustee and the Depository, of
the day on which principal, interest payable at maturity and premium, if any, is
due on this Global Security and following receipt of the necessary funds from
the Company, the Trustee shall deposit with the Depository the amount equal to
the principal, interest payable at maturity and premium, if any, by wire
transfer into the account specified by the Depository. As a condition to the
payment, on the Maturity Date or upon redemption or acceleration, of any part of
the principal and applicable premium of this Global Security, the Depository
shall surrender, or cause to be surrendered, this Global

                                       2

<PAGE>

Security to the Trustee, whereupon a new Global Security shall be issued to the
Depository.

         This Global Security is a global security in respect of a duly
authorized issue of Senior Notes, Series due 2008 (the "NOTES OF THIS SERIES",
which term includes any Global Securities representing such Notes) of the
Company issued and to be issued under an Indenture dated as of September 1, 2000
between the Company and Firstar Bank, N.A., as trustee (herein called the
"TRUSTEE", which term includes any successor Trustee under the Indenture) and
indentures supplemental thereto (collectively, the "INDENTURE"). Under the
Indenture, one or more series of Securities may be issued and, as used herein,
the term "Securities" refers to the Notes of this Series and any other
outstanding series of Securities. Reference is hereby made for a more complete
statement of the respective rights, limitations of rights, duties and immunities
under the Indenture of the Company, the Trustee and the Securityholders and of
the terms upon which the Securities are and are to be authenticated and
delivered. This Global Security has been issued in respect of the series
designated on the first page hereof, limited in aggregate principal amount to
$80,000,000.

         Each Note of this Series shall be dated and issued as of the date of
its authentication by the Trustee and shall bear an Original Issue Date or
Dates. Each Security or Global Security issued upon transfer, exchange or
substitution of such Security or Global Security shall bear the Original Issue
Date or Dates of such transferred, exchanged or substituted Security or Global
Security, as the case may be.

         The Company may redeem the Notes of this Series at any time, in whole
or in part, at a redemption price equal to the greater of (i) the principal
amount of such Notes of this Series to be redeemed or (ii) the sum of the
present values of the remaining scheduled payments of principal and interest
thereon, discounted to the date of redemption on a semi-annual basis (assuming a
360-day year consisting of twelve 30-day months) at the Treasury Yield (as
defined below) plus 15 basis points, plus in each case accrued interest thereon
to the date of redemption.

                  "Treasury Yield" means, with respect to any redemption date,
         the rate per annum equal to the semiannual equivalent yield to maturity
         of the Comparable Treasury Issue, assuming a price for the Comparable
         Treasury Issue (expressed as a percentage of its principal amount)
         equal to the Comparable Treasury Price for the redemption date.

                  "Comparable Treasury Issue" means the United States Treasury
         security selected by an Independent Investment Banker as having a
         maturity comparable to the remaining term of the Notes of this Series
         that would be utilized, at the time of selection and in accordance with
         customary financial practice, in pricing new issues of corporate debt
         securities of comparable maturity to the remaining term of the Notes.

                                       3
<PAGE>

                  "Independent Investment Banker" means Salomon Smith Barney
         Inc. or its successor or, if such firm is unwilling or unable to select
         the Comparable Treasury Issue, one of the remaining Reference Treasury
         Dealers appointed by the Trustee after consultation with the Company.

                  "Comparable Treasury Price" means, with respect to any
         redemption date, (i) the average of the bid and asked prices for the
         Comparable Treasury Issue (expressed in each case as a percentage of
         its principal amount) on the third business day preceding such
         redemption date, as set forth in the daily statistical release (or any
         successor release) published by the Federal Reserve Bank of New York
         and designated "Composite 3:30 p.m. Quotations for U.S. Government
         Securities" or (ii) if that release (or any successor release) is not
         published or does not contain such prices on such business day, (A) the
         average of the Reference Treasury Dealer Quotations for such redemption
         date, after excluding the highest and lowest such Reference Treasury
         Dealer Quotations for such redemption date, or (B) if fewer than four
         such Reference Treasury Dealer Quotations are obtained, then the
         average of all such Quotations.

                  "Reference Treasury Dealer Quotations" means, with respect to
         each Reference Treasury Dealer and any redemption date, the average, as
         determined by the Debt Trustee, of the bid and asked prices for the
         Comparable Treasury Issue (expressed in each case as a percentage of
         its principal amount) quoted in writing to the Trustee by such
         Reference Treasury Dealer at 5:00 p.m. on the third business day
         preceding such redemption date.

                  "Reference Treasury Dealer" means (i) each of Salomon Smith
         Barney Inc. and any other primary U.S. Government Securities dealer in
         New York City (a "Primary Treasury Dealer") designated by, and not
         affiliated with, Salomon Smith Barney Inc., provided, however, that if
         Salomon Smith Barney Inc. or any of its designees shall cease to be a
         Primary Treasury Dealer, the Company shall substitute another Primary
         Treasury Dealer as a substitute for such entity and (ii) any other
         Primary Treasury Dealer selected by the Company.

Notice of redemption will be given by mail to Holders of Notes of this Series
not less than 30 or more than 60 days prior to the date fixed for redemption,
all as provided in the Indenture. In the event of redemption of this Global
Security in part only, a new Global Security or Securities of like tenor and
series for the unredeemed portion hereof will be issued in the name of the
Securityholder hereof upon the surrender hereof.

         Interest payments for this Global Security shall be computed and paid
on the basis of a 360-day year of twelve 30-day months. In any case where any
Interest Payment Date or date on which the principal of this Global Security is
required to be paid is not a Business Day, then payment of principal, premium or
interest need not be made on such date but may be made on the next succeeding
Business Day with the same force and effect as if made on such Interest Payment
Date or date on which the principal of this

                                       4
<PAGE>

Global Security is required to be paid and, in the case of timely payment
thereof, no interest shall accrue for the period from and after such Interest
Payment Date or the date on which the principal of this Global Security is
required to be paid.

         The Company, at its option, and subject to the terms and conditions
provided in the Indenture, will be discharged from any and all obligations in
respect of the Securities (except for certain obligations including obligations
to register the transfer or exchange of Securities, replace stolen, lost or
mutilated Securities, maintain paying agencies and hold monies for payment in
trust, all as set forth in the Indenture) if the Company deposits with the
Trustee money, U.S. Government Obligations which through the payment of interest
thereon and principal thereof in accordance with their terms will provide money,
or a combination of money and U.S. Government Obligations, in any event in an
amount sufficient, without reinvestment, to pay all the principal of and any
premium and interest on the Securities on the dates such payments are due in
accordance with the terms of the Securities.

         If an Event of Default shall occur and be continuing, the principal of
the Securities may be declared due and payable in the manner and with the effect
provided in the Indenture.

         The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modifications of the rights and obligations of the
Company and the rights of the Securityholders under the Indenture at any time by
the Company and the Trustee with the consent of the Holders of not less than a
majority in principal amount of the outstanding Securities. Any such consent or
waiver by the Holder of this Global Security shall be conclusive and binding
upon such Holder and upon all future Holders of this Global Security and of any
Note issued upon the registration of transfer hereof or in exchange therefor or
in lieu thereof whether or not notation of such consent or waiver is made upon
the Note.

         As set forth in and subject to the provisions of the Indenture, no
Holder of any Securities will have any right to institute any proceeding with
respect to the Indenture or for any remedy thereunder unless such Holder shall
have previously given to the Trustee written notice of a continuing Event of
Default with respect to such Securities, the Holders of not less than a majority
in principal amount of the outstanding Securities affected by such Event of
Default shall have made written request and offered reasonable indemnity to the
Trustee to institute such proceeding as Trustee and the Trustee shall have
failed to institute such proceeding within 60 days; PROVIDED, HOWEVER, that such
limitations do not apply to a suit instituted by the Holder hereof for the
enforcement of payment of the principal of and any premium or interest on this
Note on or after the respective due dates expressed here.

         No reference herein to the Indenture and to provisions of this Global
Security or of the Indenture shall alter or impair the obligation of the
Company, which is absolute and unconditional, to pay the principal of and any
premium and interest on this Global

                                       5
<PAGE>

Security at the times, places and rates and the coin or currency prescribed in
the Indenture.

         As provided in the Indenture and subject to certain limitations therein
set forth, this Global Security may be transferred only as permitted by the
legend hereto.

         If at any time the Depository for this Global Security notifies the
Company that it is unwilling or unable to continue as Depository for this Global
Security or if at any time the Depository for this Global Security shall no
longer be eligible or in good standing under the Securities Exchange Act of
1934, as amended, or other applicable statute or regulation, the Company shall
appoint a successor Depository with respect to this Global Security. If a
successor Depository for this Global Security is not appointed by the Company
within 90 days after the Company receives such notice or becomes aware of such
ineligibility, the Company's election to issue this Note in global form shall no
longer be effective with respect to this Global Security and the Company will
execute, and the Trustee, upon receipt of a Company Order for the authentication
and delivery of individual Notes of this Series in exchange for this Global
Security, will authenticate and deliver individual Notes of this Series of like
tenor and terms in definitive form in an aggregate principal amount equal to the
principal amount of this Global Security.

         The Company may at any time and in its sole discretion determine that
all Notes of this Series (but not less than all) issued or issuable in the form
of one or more Global Securities shall no longer be represented by such Global
Security or Securities. In such event, the Company shall execute, and the
Trustee, upon receipt of a Company Order for the authentication and delivery of
individual Notes of this Series in exchange for such Global Security, shall
authenticate and deliver, individual Notes of this Series of like tenor and
terms in definitive form in an aggregate principal amount equal to the principal
amount of such Global Security or Securities in exchange for such Global
Security or Securities.

         Under certain circumstances specified in the Indenture, the Depository
may be required to surrender any two or more Global Securities which have
identical terms (but which may have differing Original Issue Dates) to the
Trustee, and the Company shall execute and the Trustee shall authenticate and
deliver to, or at the direction of, the Depository a Global Security in
principal amount equal to the aggregate principal amount of, and with all terms
identical to, the Global Securities surrendered thereto and that shall indicate
all Original Issue Dates and the principal amount applicable to each such
Original Issue Date.

         The Indenture and the Securities shall be governed by, and construed in
accordance with, the laws of the State of Wisconsin.

         Unless the certificate of authentication hereon has been executed by
the Trustee, directly or through an Authenticating Agent by manual signature of
an authorized officer,

                                       6
<PAGE>

this Global Security shall not be entitled to any benefit under the Indenture or
be valid or obligatory for any purpose.

         All terms used in this Global Security which are defined in the
Indenture shall have the meanings assigned to them in the Indenture unless
otherwise indicated herein.

         IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed.

                                          NORTHERN STATES POWER COMPANY

                                          By:
Dated:                                       ----------------------------------
                                          Title:
                                                -------------------------------
                                          Attest:
                                                 ------------------------------
                                          Title:
                                                -------------------------------
        TRUSTEE'S CERTIFICATE
         OF AUTHENTICATION

This Note is one of the Securities of
the series herein designated,
described or provided for in the
within-mentioned Indenture.

FIRSTAR BANK, N.A., AS TRUSTEE



By:
  -------------------------------
         AUTHORIZED OFFICER




                                       7
<PAGE>

                                  ABBREVIATIONS

The following abbreviations, when used in the inscription on the face of this
instrument, shall be construed as though they were written out in full according
to applicable laws or regulations:

TEN COM -- as tenants
in common                               UNIF GIFT
                                        MIN ACT -- _____ Custodian ____________
                                                  (Cust)              (Minor)

TEN ENT -- as tenants by
the entireties                          Under Uniform Gifts to Minors


JT TEN -- as joint tenants with         -----------------------------------
right of survivorship and not                       State
as tenants in common


                    Additional abbreviations may also be used
                          though not in the above list.

                            ------------------------

               FOR VALUE RECEIVED the undersigned hereby sell(s),
                         assign(s) and transfer(s) unto

PLEASE INSERT SOCIAL SECURITY OR OTHER
IDENTIFYING NUMBER OF ASSIGNEE

-------------------------------------------------------------------------------
                   Please print or typewrite name and address
                      including postal zip code of assignee


the within security and all rights
thereunder, hereby irrevocably
constituting and appointing
____________ attorney to transfer
said security on the books of the
Company, with full power of
substitution in the premises.

Dated:
      ------------------------------
                                                     ---------------------------
                                                     NOTICE: The signature to
                                                     this assignment must
                                                     correspond with the name as
                                                     written upon the face of
                                                     the within instrument in
                                                     every particular, without
                                                     alteration or enlargement
                                                     or any change whatever.

                                       8